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Background and Aims: Cystinuria represents 3% of nephrolithiasis in humans. Two genes have been identified as the main genetic causes of cystinuria, SLC3A1 and SLC7A9, with an autosomal recessive mode of inheritance. In the present study, we studied for the first time, genetically and clinically, all the cystinuric families identified so far in the Greek-Cypriot population. Methods: Discovery of mutations was performed through polymerase chain reaction (PCR)-single analysis and DNA resequencing. New families were investigated through PCR-RFLPs. Clinical data were collected through the hospital patients' records and analytical follow-up of the families. Results and Discussion: We found a total of five mutations in 28 Greek-Cypriot cystinuric patients belonging in 12 families. The most frequent mutation among the 28 Greek-Cypriot patients is the SLC3A1-p.T216M, which is also the second most frequent mutation in Europe, representing a genetic founder effect. Sixteen of the 28 patients are homozygous for this mutation. Even though a consanguinity loop was obvious in only one family, other patients were from families in small villages where endogamy was practiced for many centuries. Timely clinical and genetic diagnosis, accompanied by early treatment, is significant for the good health of most of our patients. Only ∼14% of them developed chronic renal failure, and only one reached end-stage renal disease (ESRD). Conclusion: Five SLC3A1 and SLC7A9 mutations appear to be responsible for the genetic basis of cystinuria in the Greek-Cypriot patients having such a limited number of causative mutations will simplify diagnostics for this population. © Copyright 2015, Mary Ann Liebert, Inc. 19 641 645

Alport syndrome (AS) is a genetic disease characterized by haematuric glomerulopathy variably associated with hearing loss and anterior lenticonus. It is caused by mutations in the COL4A3, COL4A4 or COL4A5 genes encoding the a3a4a5(IV) collagen heterotrimer. AS is rare, but it accounts for >1% of patients receiving renal replacement therapy. Angiotensin-converting enzyme inhibition slows, but does not stop, the progression to renal failure therefore, there is an urgent requirement to expand and intensify research towards discovering new therapeutic targets and new therapies. The 2015 International Workshop on Alport Syndrome targeted unmet needs in basic science, genetics and diagnosis, clinical research and current clinical care. In three intensive days, more than 100 international experts including physicians, geneticists, researchers from academia and industry, and patient representatives from all over the world participated in panel discussions and breakout groups. This report summarizes the most important priority areas including (i) understanding the crucial role of podocyte protection and regeneration, (ii) targeting mutations by new molecular techniques for new animal models and potential gene therapy, (iii) creating optimal interaction between nephrologists and geneticists for early diagnosis, (iv) establishing standards for mutation screening and databases, (v) improving widespread accessibility to current standards of clinical care, (vi) improving collaboration with the pharmaceutical/biotech industry to investigate new therapies, (vii) research in hearing loss as a huge unmet need in Alport patients and (viii) the need to evaluate the risk and benefit of novel (including 'repurposing') therapies on an international basis. © The Author 2016. 32 916 924 Cited By :1

The thirty-Third author's name is spelled incorrectly. The correct name is: Jadranka Sertić. © 2017 Mizzi et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. 12

Acknowledgments: The Euro-PGx project was partly funded by European grant (RD-Connect; FP7-305444) and the Golden Helix Foundation and encouraged by the Genomic Medicine Alliance Pharmacogenomics Working group. The Lithuanian segment of the project was supported by the LITGEN project (VP1-3.1-ŠMM-07-K-01-013), funded by the European Social Fund under the Global Grant Measure. The Czech segment of the project was supported by 00064203, LN14073, LM2015091, NF-CZ11-PDP-3-003-2014 and CZ.2.16/3.1.00/24022OPPK grants to MM. JK was funded by the National Institutes of Health Common Fund Award NHGRI Grant Number U41HG006941. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The authors declare no conflict of interests., Pharmacogenomics aims to correlate inter-individual differences of drug efficacy and/or toxicity with the underlying genetic composition, particularly in genes encoding for protein factors and enzymes involved in drug metabolism and transport. In several European populations, particularly in countries with lower income, information related to the prevalence of pharmacogenomic biomarkers is incomplete or lacking. Here, we have implemented the microattribution approach to assess the pharmacogenomic biomarkers allelic spectrum in 18 European populations, mostly from developing European countries, by analyzing 1,931 pharmacogenomics biomarkers in 231 genes. Our data show significant interpopulation pharmacogenomic biomarker allele frequency differences, particularly in 7 clinically actionable pharmacogenomic biomarkers in 7 European populations, affecting drug efficacy and/or toxicity of 51 medication treatment modalities. These data also reflect on the differences observed in the prevalence of high-risk genotypes in these populations, as far as common markers in the CYP2C9, CYP2C19, CYP3A5, VKORC1, SLCO1B1 and TPMT pharmacogenes are concerned. Also, our data demonstrate notable differences in predicted genotype-based warfarin dosing among these populations. Our findings can be exploited not only to develop guidelines for medical prioritization, but most importantly to facilitate integration of pharmacogenomics and to support pre-emptive pharmacogenomic testing. This may subsequently contribute towards significant cost-savings in the overall healthcare expenditure in the participating countries, where pharmacogenomics implementation proves to be cost-effective., The Euro-PGx project was partly funded by European grant (RD-Connect; FP7-305444) and the Golden Helix Foundation and encouraged by the Genomic Medicine Alliance Pharmacogenomics Working group. The Lithuanian segment of the project was supported by the LITGEN project (VP1- 3.1-ŠMM-07-K-01-013), funded by the European Social Fund under the Global Grant Measure. The Czech segment of the project was supported by 00064203, LN14073, LM2015091, NF-CZ11-PDP-3-003-2014 and CZ.2.16/3.1.00/24022OPPK grants to MM. JK was funded by the National Institutes of Health Common Fund Award NHGRI Grant Number U41HG006941. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript., peer-reviewed

Background The archeological record indicates that the permanent settlement of Cyprus began with pioneering agriculturalists circa 11,000 years before present, (ca. 11,000 y BP). Subsequent colonization events followed, some recognized regionally. Here, we assess the Y-chromosome structure of Cyprus in context to regional populations and correlate it to phases of prehistoric colonization. Results Analysis of haplotypes from 574 samples showed that island-wide substructure was barely significant in a spatial analysis of molecular variance (SAMOVA). However, analyses of molecular variance (AMOVA) of haplogroups using 92 binary markers genotyped in 629 Cypriots revealed that the proportion of variance among the districts was irregularly distributed. Principal component analysis (PCA) revealed potential genetic associations of Greek-Cypriots with neighbor populations. Contrasting haplogroups in the PCA were used as surrogates of parental populations. Admixture analyses suggested that the majority of G2a-P15 and R1b-M269 components were contributed by Anatolia and Levant sources, respectively, while Greece Balkans supplied the majority of E-V13 and J2a-M67. Haplotype-based expansion times were at historical levels suggestive of recent demography. Conclusions Analyses of Cypriot haplogroup data are consistent with two stages of prehistoric settlement. E-V13 and E-M34 are widespread, and PCA suggests sourcing them to the Balkans and Levant/Anatolia, respectively. The persistent pre-Greek component is represented by elements of G2-U5(xL30) haplogroups: U5*, PF3147, and L293. J2b-M205 may contribute also to the pre-Greek strata. The majority of R1b-Z2105 lineages occur in both the westernmost and easternmost districts. Distinctively, sub-haplogroup R1b- M589 occurs only in the east. The absence of R1b- M589 lineages in Crete and the Balkans and the presence in Asia Minor are compatible with Late Bronze Age influences from Anatolia rather than from Mycenaean Greeks. Electronic supplementary material The online version of this article (doi:10.1186/s13323-016-0032-8) contains supplementary material, which is available to authorized users.

Background Familial hematuria (FH) is associated with at least two pathological entities: Thin basement membrane nephropathy (TBMN), caused by heterozygous COL4A3/ COL4A4 mutations, and C3 nephropathy caused by CFHR5 mutations. It is now known that TBMN patients develop proteinuria and changes of focal segmental glomerulosclerosis when biopsied. End-stage kidney disease (ESKD) is observed in 20% of carriers, at ages 50-70. A similar progression is observed in CFHR5 nephropathy. Recent evidence suggests that NPHS2-R229Q, a podocin polymorphism, may contribute to proteinuria in TBMN and to micro-albuminuria in the general population. Case-Diagnosis/Treatment NPHS2-R229Q was screened in a Cypriot FH cohort. 102 TBMN patients with three known COL4 mutations and 45 CFHR5 male patients with a single mutation were categorized as "Mild" or "Severe", based on the presence of microhematuria only, or proteinuria and chronic kidney disease. Nine R229Q carriers were found in the "Severe" category and none in the "Mild" (p00.010 for genotypic association p00.043 for allelic association, adjusted for patients' relatedness), thus supporting the possible contribution of 229Q allele in disease progress. Conclusions Our results offer more evidence that in patients with FH, NPHS2-R229Q predisposes to proteinuria and ESKD. R229Q may be a good prognostic marker for young hematuric patients © IPNA 2011. 27 675 679 Cited By :23

Alport syndrome (AS) is a hereditary progressive glomerulonephritis with a high life-time risk for end-stage renal disease (ESRD). Most patients will reach ESRD before the age of 30 years, while a subset of them with milder mutations will do so at older ages, even after 50 years. Frequent extrarenal manifestations are hearing loss and ocular abnormalities. AS is a genetically heterogeneous collagen IV nephropathy, with 85% of the cases caused by mutations in the X-linked COL4A5 gene and the rest by homozygous or compound heterozygous mutations in either the COL4A3 or the COL4A4 gene on chromosome 2q36-37. There is no radical cure for the disease and attempts to use various stem cell therapies in animal models have been met with ambiguous success. However, effective treatment has been accomplished with pharmacological intervention at the renin-angiotensin-aldosterone system (RAAS), first in animal models of AS and more recently in humans. Angiotensin converting enzyme inhibitors (ACEis) and angiotensin receptor blockers (ARBs) have been shown to significantly delay the progression of chronic kidney disease and the onset of ESRD. Also, renin inhibitors and aldosterone blockade were used with positive results, while the combination of ACEis and ARBs was met with mixed success. An important study, the EARLY-PROTECT, aims at evaluating the efficacy of ACEis when administered very early on in children with AS. Novel therapies are also tested experimentally or are under design in animal models by several groups, including the use of amniotic fluid stem cells and synthetic chaperones. 107 205 210 Cited By :3

Familial microscopic hematuria (MH) of glomer-ular origin represents a heterogeneous group of monogenic conditions involving several genes, some of which remain unknown. Recent advances have increased our understanding and our ability to use molecular genetics for diagnosing such patients, enabling us to study their clinical characteristics over time. Three collagen IV genes, COL4A3, COL4A4, and COL4A5 explain the autosomal and X-linked forms of Alport syndrome (AS), and a subset of thin basement membrane nephropathy (TBMN). A number of X-linked AS patients follow a milder course reminiscent of that of patients with heterozygous COL4A3/COL4A4 mutations and TBMN, while at the same time a significant subset of patients with TBMN and familial MH progress to chronic kidney disease (CKD) or end-stage kidney disease (ESKD). A mutation in CFHR5, a member of the complement factor H family of genes that regulate complement activation, was recently shown to cause isolated C3 glomerulopathy, presenting with MH in childhood and demonstrating a significant risk for CKD/ ESKD after 40 years old. Through these results molecular genetics emerges as a powerful tool for a definite diagnosis when all the above conditions enter the differential diagnosis, while in many at-risk related family members, a molecular diagnosis may obviate the need for another renal biopsy. © 2011 IPNA. 27 1221 1231 Cited By :25

Background and objectives Complement factor H and related proteins (CFHR) are key regulators of the alternative complement pathway, where loss of function mutations lead to a glomerulopathy with isolated mesangial C3 deposits without immunoglobulins. Gale et al. (12) reported on 26 patients with the first familial, hematuric glomerulopathy caused by a founder mutation in the CFHR5 gene in patients of Cypriot descent living in the United Kingdom. CFHR5 nephropathy is clinically characterized by continuous microscopic hematuria whereas some patients present with additional episodes of synpharyngitic macrohematuria, associated with infection and pyrexia. A subgroup of patients, particularly men, develop additional proteinuria, hypertension, and chronic renal disease or ESRD. Design, setting, participants, & measurements We herewith expand significantly on the study by Gale et al., reporting on histologic, molecular, and clinical findings in 91 patients from 16 families with the same founder mutation. Results Eighty-two patients (90%) exhibited microscopic hematuria 51 (62%), exhibited only microscopic hematuria, whereas the remaining 31 additionally had proteinuria (38%) 28 proteinuric patients developed chronic renal failure (CRF). Among carriers of CFHR5 mutation aged >50 years, 80% of the men and 21% of the women developed CRF 18 developed ESRD (14 men [78%], 4 women [22%]). Conclusions The diagnosis of CFHR5-related, isolated C3 glomerulopathy was established in 2009 using newly described mutation analysis after decades of follow-up with unclear diagnoses, occasionally confused with IgA nephropathy. This larger patient cohort establishes the clinical course, significant variable expressivity, and marked gender difference regarding the development of CRF and ESRD. © 2011 by the American Society of Nephrology. 6 1436 1446 Cited By :75

Objective - Genetic polymorphisms in the gene for endothelial nitric oxide synthase have been considered as potential risk factors for the development of coronary artery disease in some populations. Methods - We studied two polymorphisms of the NOS3 gene, the VNTR in intron 4 (4VNTR) and the Glu298Asp polymorphism in exon 7, in relation to the existence of premature coronary artery disease and the occurrence of myocardial infarction. A total number of 370 individuals of the Greek population was examined by PCR-RFLP method. The patient group consisted of 209 subjects, aged less than 58 years presenting symptomatic coronary artery disease, documented by coronary angiography. Results - The frequencies for bb, ab and aa genotypes of 4VNTR polymorphism were 0.67, 0.29, 0.04, respectively, for the patient group and 0.73, 0.24, 0.03 for the control group. The frequencies for GG (Glu/ Glu), GT (Glu/Asp), TT (Asp/Asp) of the Glu298Asp polymorphism were 0.52, 0.41, 0.07, respectively, in patients compared to 0.47, 0.46, 0.07, in control subjects. Statistical analysis indicated that there are no significant differences in the frequencies of the genotypes between patients and control subjects for both polymorphisms. The combined analysis of the two polymorphisms indicated no synergistic effect of the a and T alleles on coronary artery disease. Conclusions - We have found no evidence for association between the a allele of the 4VNTR polymorphism, or the T allele of Glu298Asp polymorphism and the risk for premature coronary artery disease or occurrence of myocardial infarction. Furthermore, no synergistic contribution of these polymorphisms to the development of premature coronary artery disease has been observed. 63 609 614 Cited By :17

Mutations in the COL4A3/COL4A4 genes of type IV collagen account for about 40% of cases of thin basement membrane nephropathy, a condition that is estimated to affect 1% or more of the general population. We recently described 10 Cypriot families with familial hematuria and thin basement membrane nephropathy in the presence of focal segmental glomerulosclerosis, with founder mutations on COL4A3 gene. Seven of the families carried mutation G1334E on haplotype K, and another three carried mutation G871C on haplotype Ky. In this report we performed extension of the haplotypes with additional polymorphic markers, 12 for haplotype K and 22 for haplotype Ky, to estimate the linkage disequilibrium value between the mutation and flanking noncommon markers. Haplotype Ky extended to 13.71 Mb, but we did not attempt further analysis owing to the small number of chromosomes. Haplotype K extended to 3.83 Mb, thereby suggesting that it was a much older event compared to mutation G871C. Mutation G1334E was calculated to be about 5-10 generations old with a possible origin between 1693 and 1818 AD, during the Ottoman ruling of the island. Both mutations are clustered in specific geographic regions with apparently formerly isolated populations, although mutation G1334E has been detected elsewhere on the island. The identification of founder mutations in large families with microscopic hematuria greatly facilitates presymptomatic diagnosis and provides useful information on the history of the population, while it may also assist in association studies in search for disease modifier genes. © Copyright, Mary Ann Liebert, Inc. 2008. 12 273 278 Cited By :10

Collagen IV nephropathies (COL4Ns) comprise benign familial microscopic hematuria, thin basement membrane nephropathy (TBMN), X-linked Alport syndrome (AS) and also autosomal recessive and dominant AS. Apart from the X-linked form of AS, which is caused by hemizygous mutations in the COL4A5 gene, the other entities are caused by mutations in the COL4A3 or COL4A4 genes. The diagnosis of these conditions used to be based on clinical and/or histological findings of renal biopsies, but it is the new molecular genetics approach that revolutionised their investigation and proved particularly instrumental, especially, in many not so clear-cut cases. More recently, the spectrum of COL4N has expanded to include late onset focal segmental glomerulosclerosis (FSGS) that develops on top of TBMN in later life. Also, other reports showed that some patients with a primary diagnosis of familial FSGS proved to have variants in COL4 genes. In the presence of a renal biopsy picture of FSGS and in the absence of either electron microscopy studies or molecular genetic studies that point to TBMN and COL4N, the patient and his family may be mistakenly diagnosed with hereditary FSGS leading to unnecessary further investigations, erroneous family counselling and improper corticosteroid treatment. TBMN is a frequent finding in the general population, and according to several recent reports, it may be the underlying cause and the explanation for many familial and sporadic cases of late-onset FSGS with non-nephrotic proteinuria. This is an important new finding that needs widespread recognition. It is anticipated that the molecular genetic analysis with next generation sequencing will certainly offer timely correct diagnosis.

Background/Aims: A subset of patients who present with proteinuria and are diagnosed with focal segmental glomerulosclerosis (FSGS) have inherited heterozygous COL4A3/A4 mutations and are also diagnosed with thin basement membrane nephropathy (TBMN-OMIM: 141200). Two studies showed that co-inheritance of NPHS2-p.Arg229Gln, a podocin variant, may increase the risk for proteinuria and renal function decline. Methods: We hypothesized that additional podocin variants may exert a similar effect. We studied genetically a well-characterized Cypriot TBMN patient cohort by re-sequencing the NPHS2 coding region. We also performed functional studies in cell culture experiments, investigating the interaction of podocin variants with itself and with nephrin. Results: Potentially disease-modifying podocin variants were searched for by analyzing NPHS2 in 35 ‘severe' TBMN patients. One non-synonymous variant, p.Glu237Gln, was detected. Both variants, p.Arg229Gln and p.Glu237Gln, were tested in a larger cohort of 122 TBMN patients, who were categorized as ‘mild' or ‘severe' based on the presence of microscopic hematuria alone or combined with chronic renal failure and/or proteinuria. Seven ‘severe' patients carried either of the 2 variants; none was present in the ‘mild' patients (p = 0.05, Pearson χ2). The 7 carriers belong in 2 families segregating mutation COL4A3-p.Gly1334Glu. Inheritance of the wild-type (WT) and mutant alleles correlated with the phenotype (combined concordance probability 0.003). Immunofluorescence (IF) experiments after dual co-transfection of WT and mutant podocin suggested altered co-localization of mutant homodimers. IF experiments after co-transfection of WT podocin and nephrin showed normal membrane localization, while both podocin variants interfered with normal trafficking, demonstrating perinuclear staining. Immunoprecipitation experiments showed stronger binding of mutant podocin to WT podocin or nephrin. Conclusion: The results support the hypothesis that certain hypomorphic podocin variants may act as adverse genetic modifiers when co-inherited with COL4A3/A4 mutations, thus predisposing to FSGS and severe kidney function decline.

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Rare autosomal dominant tubulointerstitial kidney disease is caused by mutations in the genes encoding uromodulin (UMOD), hepatocyte nuclear factor-1β (HNF1B), renin (REN), and mucin-1 (MUC1). Multiple names have been proposed for these disorders, including 'Medullary Cystic Kidney Disease (MCKD) type 2', 'Familial Juvenile Hyperuricemic Nephropathy (FJHN)', or 'Uromodulin-Associated Kidney Disease (UAKD)' for UMOD-related diseases and 'MCKD type 1' for the disease caused by MUC1 mutations. The multiplicity of these terms, and the fact that cysts are not pathognomonic, creates confusion. Kidney Disease: Improving Global Outcomes (KDIGO) proposes adoption of a new terminology for this group of diseases using the term 'Autosomal Dominant Tubulointerstitial Kidney Disease' (ADTKD) appended by a gene-based subclassification, and suggests diagnostic criteria. Implementation of these recommendations is anticipated to facilitate recognition and characterization of these monogenic diseases. A better understanding of these rare disorders may be relevant for the tubulointerstitial fibrosis component in many forms of chronic kidney disease. 88 676 683 Cited By :41

Germ-line mutations of the RET proto-oncogene cause three different cancer syndromes: multiple endocrine neoplasia type 2A (MEN2A), multiple endocrine neoplasia type 2B, and familial medullary thyroid carcinoma (FMTC). The objective of the present study was the clinical and molecular characterization of the first two Greek Cypriot families diagnosed with MEN2A and FMTC. The clinical diagnosis of the probands was based on clinical presentation and supported with laboratory findings (calcitonin and carcinoembryonic antigen tumor marker levels). We screened the RET gene by direct DNA sequencing of exons 10, 11, and 16 using genomic DNA as templates. After identification of the mutation, we also developed the amplification refractory mutation system (ARMS) as an alternative method to direct sequencing for genetic diagnosis of 22 additional individuals from both families. We identified the germ-line missense mutation T → C of codon 618 of exon 10 (C618R) in the probands of both families. By using ARMS, two members of the MEN2A family and five members of the FMTC family were also found positive for the C618R mutation. These are the first seemingly unrelated families in Cyprus investigated clinically and molecularly in detail and shown to transmit this common RET proto-oncogene mutation. 8 163 168 Cited By :7

Background: The MEFV gene is responsible for familial Mediterranean fever (FMF). Several disease associated mutations have been identified. The range of genetic variation in MEFV in Greek patients has not been determined. Objective: To describe a method that facilitates the routine screening of the entire coding sequence of MEFV (excluding exon 1). Methods: The non-isotopic RNase cleavage assay (NIRCA) was optimised and used as a first step screening method to screen exons 2 to 10 of MEFV. Exons 2 and 10 were analysed separately at DNA level, while exons 3 to 9 were analysed together at cDNA level. The sample group consisted of 26 FMF patients diagnosed using established clinical criteria, six asymptomatic relatives, 12 patients with atypical clinical manifestations, nine patients suffering from various inflammatory diseases, and three normal individuals. All were analysed by NIRCA for mutations in the MEFV gene and direct sequencing was applied subsequently to confirm the results. Results: MEFV mutations were identified in 25 of 26 typical FMF patients and in two of 12 patients with atypical manifestations. NIRCA results were in concordance with sequencing findings in all sequences analysed, suggesting that the method is highly reliable in this disease. Sixteen alterations of MEFV were identified (eight missense mutations and eight single nucleotide polymorphisms). Conclusions: NIRCA can be used for rapid screening of the coding sequence of the MEFV gene in patients suspected of suffering from FMF. 63 438 443 Cited By :24

Background. Autosomal dominant medullary cystic kidney disease (ADMCKD) is an inherited, distinct, chronic, tubulointerstitial, cystic-type nephropathy, often described together with juvenile nephronophthisis as a single disease complex (NPH-MCD). However, since the recent localization of two genes responsible for ADMCKD, namely MCKD1 and MCKD2, ADMCKD has gained independent status. Unfortunately, there appears to be a distinct lack of up-to-date information in the currently available medical literature concerning worldwide patient and graft survival after renal transplantation in ADMCKD. This report is based on all 41 transplanted patients [19 suffering from autosomal dominant medullary cystic kidney disease type 1 (ADMCKD1) and 22 from other causes] who were referred for kidney transplantation from our centre in Pafos, Cyprus between 1976 and 2000. All patients had regular follow-up examinations. This report aims to present the results of kidney transplantation of the 19 ADMCKD1 patients and to compare them with those for the 22 non-ADMCKD patients. Methods. Patient and graft survival times in both groups were recorded, analysed and compared 1 and 5 years post-transplant. Patient and graft survival times were calculated according to the Kaplan-Meier method and some descriptive statistical comparisons were based on the χ2-test. Results. The 1 year patient and graft survival rates for ADMCKD1 (group A) were 100%, while the 5 year figures were 100% and 90%, respectively. For non-ADMCKD1 patients (group B) the 1 year figures were 95% for both parameters, while the 5 year figures were 93.3% for both parameters. There were no statistically significant differences in patient and graft survival times between the two groups. Conclusions. Kidney transplantation is the treatment of choice for patients suffering from ADMCKD, with an excellent outcome and no specific complications. 18 2165 2169 Cited By :10

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Background Recent data emphasize that thin basement membrane nephropathy (TBMN) should not be viewed as a form of benign familial hematuria since chronic renal failure (CRF) and even end-stage renal disease (ESRD), is a possible development for a subset of patients on longterm follow-up, through the onset of focal and segmental glomerulosclerosis (FSGS). We hypothesize that genetic modifiers may explain this variability of symptoms. Methods We looked in silico for potentially deleterious functional SNPs, using very strict criteria, in all the genes significantly expressed in the slit diaphragm (SD). Two variants were genotyped in a cohort of well-studied adult TBMN patients from 19 Greek-Cypriot families, with a homogeneous genetic background. Patients were categorized as 'Severe' or 'Mild', based on the presence or not of proteinuria, CRF and ESRD. A larger pooled cohort (HEMATURIA) of 524 patients, including IgA nephropathy patients, was used for verification. Additionally, three large general population cohorts [Framingham Heart Study (FHS), KORAF4 and SAPHIR] were used to investigate if the NEPH3-V353M variant has any renal effect in the general population. Results and conclusions Genotyping for two high-scored variants in 103 TBMN adult patients with founder mutations who were classified as mildly or severely affected, pointed to an association with variant NEPH3-V353M (filtrin). This promising result prompted testing in the larger pooled cohort (HEMATURIA), indicating an association of the 353M variant with disease severity under the dominant model (p = 3.0×103, OR = 6.64 adjusting for gender/age allelic association: P = 4.2×103 adjusting for patients' kinships). Subsequently, genotyping 6,531 subjects of the Framingham Heart Study (FHS) revealed an association of the homozygous 353M/M genotype with microalbuminuria (p = 1.0×103). Two further general population cohorts, KORAF4 and SAPHIR confirmed the association, and a meta-analysis of all three cohorts (11,258 individuals) was highly significant (p = 1.3×105, OR = 7.46). Functional studies showed that Neph3 homodimerization and Neph3-Nephrin heterodimerization are disturbed by variant 353M. Additionally, 353M was associated with differential activation of the unfolded protein response pathway, when overexpressed in stressed cultured undifferentiated podocyte cells, thus attesting to its functional significance. Genetics and functional studies support a 'rare variant-strong effect' role for NEPH3-V353M, by e×erting a negative modifier effect on primary glomerular hematuria. Additionally, genetics studies provide evidence for a role in predisposing homozygous subjects of the general population to microalbuminuria. © 2017 Voskarides et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. 12

BACKGROUND: Distal renal tubular acidosis (dRTA) is a rare genetic disease caused by mutations in different genes involved in the secretion of H+ ions in the intercalated cells of the collecting duct. Both autosomal dominant and recessive forms have been described the latter is also associated with sensorineural hearing loss. METHODS: Twenty-two Tunisian families were analyzed for mutations in the ATP6V1B1 and ATP6V0A4 genes by direct sequencing. Dating of the founder mutations was performed. RESULTS: Two founder mutations in the ATP6V1B1 gene were found in 16/27 dRTA cases. The p.Ile386Hisfs*56 founder mutation was estimated to be older than 2400 years and no correlations were found with deafness. For the remaining patients, two mutations in the ATP6V0A4 gene, one of them being novel, were found in three Tunisian cases. The presence of a heterozygous missense mutation p.T30I, of the ATP6V1B1 gene, was identified in six patients, while no mutations of the second gene were detected. No deleterious mutations of either ATP6V1B1 or ATP6V0A were found for the two probands. CONCLUSION: Our study gives evidence of phenotypic and genotypic heterogeneity of dRTA in the Tunisian population. Five different mutations were found, two of them were due to a founder effect, and screening of these mutations could provide a rapid and valuable tool for diagnosis of dRTA. 18 741 748 Cited By :5

Background Two variants in the gene encoding the cytochrome P450 2C9 enzyme (CYP2C9) are considered the most significant genetic risk factors associated with bleeding after warfarin prescription. A variant in the vitamin K epoxide reductase (VKORC1) has been also associated by several studies with warfarin response. Another variant in the P450 3A5 enzyme (CYP3A5) gene is known to affect the metabolism of many drugs, including tacrolimus. Findings We conducted a population genetic study in 148 unrelated healthy Greek-Cypriot volunteers (through PCR-RFLP assays), in order to determine the frequencies of the above pharmacogenetics variants and to compare allele frequencies with those in other major ethnic groups. The allele frequencies of CYP2C9*2, CYP2C9*3 and CYP3A5*3 were found to be 0.162, 0.112 and 0.943 respectively, whereas VKORC1 - 1639A was 0.534. The latter frequency differs significantly when compared with Caucasians, Asians and Africans (p Conclusions Our data show no significant difference in the frequency of CYP2C9 and CYP3A5 allelic variants when compared to the Caucasian population, but differ significantly when compared with Africans and Asians (p VKORC1 - 1639A differs between Greek-Cypriots and every other population we compared. Finally, about 1/5 Greek-Cypriots carry three or four risk alleles and ~50% of them carry at least two independent risk alleles regarding warfarin sensitivity, a potentially high risk for over-anticoagulation.

Background and objectives The genetic cause of medullary cystic kidney disease type 1 was recently identified as a cytosine insertion in the variable number of tandem repeat region of MUC1 encoding mucoprotein-1 (MUC1), a protein that is present in skin, breast, and lung tissue, the gastrointestinal tract, and the distal tubules of the kidney. The purpose of this investigationwas to analyze the clinical characteristics of families and individuals with this mutation. Design, setting, participants, & measurements Families with autosomal dominant interstitial kidney diseasewere referred for genetic analysis over a 14-year period. Families without UMOD or REN mutations prospectively underwent genotyping for the presence of the MUC1 mutation. Clinical characteristics were retrospectively evaluated in individuals with the MUC1 mutation and historically affected individuals (persons who were both related to genetically affected individuals in such a way that ensured that they could be genetically affected and had a history of CKD stage IV or kidney failure resulting in death, dialysis, or transplantation). Results Twenty-four families were identified with the MUC1 mutation. Of 186 family members undergoing MUC1 mutational analysis, the mutation was identified in 95 individuals, 91 individuals did not have the mutation, and111 individuals were identified as historically affected. Individuals with the MUC1 mutation suffered from chronic kidney failure with a widely variable age of onset of end stage kidney disease ranging from 16 to.80 years. Urinalyses revealed minimal protein and no blood. Ultrasounds of 35 individuals showed no medullary cysts. There were no clinical manifestations of the MUC1 mutation detected in the breasts, skin, respiratory system, or gastrointestinal tract. ConclusionMUC1 mutation results in progressive chronic kidney failurewith a bland urinary sediment. The age of onset of end stage kidney disease is highly variable, suggesting that gene-gene or gene-environment interactions contribute to phenotypic variability. © 2014 by the American Society of Nephrology. 9 527 535 Cited By :15

Familial glomerular hematuria(s) comprise a genetically heterogeneous group of conditions which include Alport Syndrome (AS) and thin basement membrane nephropathy (TBMN). Here we investigated 57 Greek-Cypriot families presenting glomerular microscopic hematuria (GMH), with or without proteinuria or chronic kidney function decline, but excluded classical AS. We specifically searched the COL4A3/A4 genes and identified 8 heterozygous mutations in 16 families (28,1%). Eight non-related families featured the founder mutation COL4A3-p.(G1334E). Renal biopsies from 8 patients showed TBMN and focal segmental glomerulosclerosis (FSGS). Ten patients (11.5%) reached end-stage kidney disease (ESKD) at ages ranging from 37-69-yo (mean 50,1-yo). Next generation sequencing of the patients who progressed to ESKD failed to reveal a second mutation in any of the COL4A3/A4/A5 genes, supporting that true heterozygosity for COL4A3/A4 mutations predisposes to CRF/ESKD. Although this could be viewed as a milder and late-onset form of autosomal dominant AS, we had no evidence of ultrastructural features or extrarenal manifestations that would justify this diagnosis. Functional studies in cultured podocytes transfected with wild type or mutant COL4A3 chains showed retention of mutant collagens and differential activation of the unfolded protein response (UPR) cascade. This signifies the potential role of the UPR cascade in modulating the final phenotype in patients with collagen IV nephropathies. © 2014 Papazachariou et al. 9 12 Cited By :13

Clear cell renal cell carcinoma (ccRCC) is the predominant subtype of renal cell carcinoma (RCC). It is one of the most therapy-resistant carcinomas, responding very poorly or not at all to radiotherapy, hormonal therapy and chemotherapy. A more comprehensive understanding of the deregulated pathways in ccRCC can lead to the development of new therapies and prognostic markers. We performed a metaanalysis of 5 publicly available gene expression datasets and identified a list of coderegulated genes, for which we performed extensive bioinformatic analysis coupled with experimental validation on the mRNA level. Gene ontology enrichment showed that many proteins are involved in response to hypoxia/oxygen levels and positive regulation of the VEGFR signaling pathway. KEGG analysis revealed that metabolic pathways are mostly altered in ccRCC. Similarly, Ingenuity Pathway Analysis showed that the antigen presentation, inositol metabolism, pentose phosphate, glycolysis/gluconeogenesis and fructose/mannose metabolism pathways are altered in the disease. Cellular growth, proliferation and carbohydrate metabolism, were among the top molecular and cellular functions of the co-deregulated genes. qRT-PCR validated the deregulated expression of several genes in Caki-2 and ACHN cell lines and in a cohort of ccRCC tissues. NNMT and NR3C1 increased expression was evident in ccRCC biopsies from patients using immunohistochemistry. ROC curves evaluated the diagnostic performance of the top deregulated genes in each dataset. We show that metabolic pathways are mostly deregulated in ccRCC and we highlight those being most responsible in its formation. We suggest that these genes are candidate predictive markers of the disease. 1 117 131 Cited By :16

The hereditary type IV collagen disease Alport syndrome (AS) always leads to end-stage renal failure. Yesterday, for the past 90 years, this course was described as 'inevitable'. Today, RAAS blockade has changed the 'inevitable' course to a treatable disease. Tomorrow, researchers hope to erase the 'always' from 'always leads to renal failure' in the textbooks. This review elucidates therapeutic targets that evolve from research: (i) kidney embryogenesis and pathogenesis (ii) phenotypegenotype correlation and the role of collagen receptors and podocytes (iii) the malfunctioning Alport-GBM (iv) tubulointerstitial fibrosis (v) the role of proteinuria in pathogenesis and prognosis and (vi) secondary events such as infections, hyperparathyroidism and hypercholesterolaemia. Therefore, moderate lifestyle, therapy of bacterial infections, Paricalcitol in adult patients with hyperparathyroidism and HMG-CoAreductase inhibitors in adult patients with dyslipoproteinemia might contribute to a slower progression of AS and less cardiovascular events. In the future, upcoming treatments including stem cells, chaperon therapy, collagen receptor blockade and anti-microRNA therapy will expand our perspective in protecting the kidneys of Alport patients from further damage. This perspective on current and future therapies is naturally limited by our personal focus in research, but aims to motivate young scientists and clinicians to find a multimodal cure for AS. © The Author 2014. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved. 29 iv124 iv130 Cited By :14

X-linked Alport syndrome is a form of progressive renal failure caused by pathogenic variants in the COL4A5 gene. More than 700 variants have been described and a further 400 are estimated to be known to individual laboratories but are unpublished. The major genetic testing laboratories for X-linked Alport syndrome worldwide have established a Web-based database for published and unpublished COL4A5 variants ( https://grenada.lumc.nl/LOVD2/COL4A/home.php?select_db=COL4A5 ). This conforms with the recommendations of the Human Variome Project: it uses the Leiden Open Variation Database (LOVD) format, describes variants according to the human reference sequence with standardized nomenclature, indicates likely pathogenicity and associated clinical features, and credits the submitting laboratory. The database includes non-pathogenic and recurrent variants, and is linked to another COL4A5 mutation database and relevant bioinformatics sites. Access is free. Increasing the number of COL4A5 variants in the public domain helps patients, diagnostic laboratories, clinicians, and researchers. The database improves the accuracy and efficiency of genetic testing because its variants are already categorized for pathogenicity. The description of further COL4A5 variants and clinical associations will improve our ability to predict phenotype and our understanding of collagen IV biochemistry. The database for X-linked Alport syndrome represents a model for databases in other inherited renal diseases.

There is a group of inherited cystic nephropathies that are characterized by juvenile onset recessive inheritance (familial juvenile nephronophthisis, FJN) or by adult onset dominant inheritance (medullary cystic disease, MCD) and share similar clinico-pathological presentation to the extent that they are usually grouped together under the term FJN/MCD complex. The main symptoms consist of renal cyst formation in the medulla or the corticomedullary junction and salt wasting. Although earlier reports had suggested that one single gene may be responsible for this pathology, recent reports have shown that the FJN complex itself comprises a genetically heterogeneous group. Here we are presenting two large Cypriot families that segregate autosomal dominant medullary cystic kidney disease (ADMCKD) with hyperuricemia and gout and with very late age of onset (mean 62.2 and 51.5 years). We performed DNA linkage mapping using highly polymorphic microsatellite markers and found linkage to marker locus D1S1595 at 1q21 with a two-point lod score of 6.45 at θ = 0.00. Analysis of haplotypes and of critical recombinants enabled confinement of the disease locus within an ~ 8 cM region between marker loci D1S498 and D1S2125. FISH mapping with a large P1 clone confirmed the physical localization within 1q21. The two families share the same disease haplotype, thus suggesting their relationship through a common ancestor and the possible existence of a single ADMCKD-causing mutation within these families. To our knowledge this is the first genetic locus identified to cause FJN/MCD pathology of the dominant adult type. 7 905 911 Cited By :99

Mutations in the PKD2 gene on the long arm of chromosome 4 are responsible for ~ 15% of cases of polycystic kidney disease. Perhaps the only difference from the more common ADPKD1 cases is the rate of progression of cystic changes, and the age of onset, which is 10-15 years later for the ADPKD2 form. In Cyprus there are at least three large families, documented by molecular linkage analysis, that map to the PKD2 locus. For two of them the defects were recently shown to be nonsense mutations at positions arginine 742 and glutamine 405. In this report, we describe the mutation in the third family, CY1602. For this, the entire coding sequence was systematically screened by single strand conformation analysis and heteroduplex formation. A novel mutation was identified in exon 2 where a new cytosine residue was inserted immediately after codon 231 (231insC). It causes a translation frameshift and is expected to lead to the introduction of 37 novel amino acids before the translation reaches a new STOP codon. It is the most amino terminal mutation reported to date, and based on the protein's modeled structure, is predicted to be within the first transmembrane domain. It is the fourth PKD2 mutation reported thus far, and the first which is not a nonsense mutation. 6 949 952 Cited By :22

Familial Mediterranean fever (FMF) is an autoinflammatory disease inherited as an autosomal recessive condition and characterized by recurrent episodes of fever, abdominal pain, pleuritis, and arthritis (1)(2). The most dangerous manifestation is renal amyloidosis and end-stage renal failure. Many researchers have associated the M694V mutation (3)(4)(5) as well as the α allele of serum amyloid A protein I with significantly higher risk for amyloidosis (6). FMF is very prevalent in non-Ashkenazi Jews, Armenians, Arabs, and Turks, all of whom have ancestors of Mediterranean origin. The carrier frequency in these populations can reach up to 1:5, rendering it the most frequent autosomal recessive condition. Currently, it is considered frequent in other Mediterranean countries, including Cyprus (7)(8)(9)(10)(11). The gene associated with FMF, MEFV , which encodes pyrin/marenostrin, a protein of 781 amino acids (12)(13), belongs to the pyrin family of genes that play a role in autoinflammatory diseases and inflammatory pathways (14)(15). More than 40 mutations have been identified, but 4–6 mutations usually account for a high percentage of MEFV chromosomes in different ethnic populations, emphasizing the importance of molecular epidemiologic studies for identifying the various molecular defects in the population of interest. The detection of known mutations in MEFV can be accomplished by various methods, including direct DNA sequencing. These methods are time-consuming and prone to carryover PCR contamination because of the repetitive work in a diagnostic setting. Using fluorescence resonance energy transfer (FRET) on a LightCycler® instrument (Roche), we developed a rapid method that detects point mutations and small deletions by use of fluorescent hybridization probes. Because of the close proximity of several mutations on exon 10, we designed a single pair of fluorescent probes with multiplex melting profiles that permits …

The familial hematuric diseases are a genetically heterogeneous group of monogenic conditions, caused by mutations in one of several genes. The major genes involved are the following: (i) the collagen IV genes COL4A3/A4/A5 that are expressed in the glomerular basement membranes (GBM) and are responsible for the most frequent forms of microscopic hematuria, namely Alport syndrome (X-linked or autosomal recessive) and thin basement membrane nephropathy (TBMN). (ii) The FN1 gene, expressed in the glomerulus and responsible for a rare form of glomerulopathy with fibronectin deposits (GFND). (iii) CFHR5 gene, a recently recognized regulator of the complement alternative pathway and mutated in a recently revisited form of inherited C3 glomerulonephritis (C3GN), characterized by isolated C3 deposits in the absence of immune complexes. A hallmark feature of all conditions is the age-dependent penetrance and a broad phenotypic heterogeneity in the sense that subsets of patients progress to added proteinuria or proteinuria and chronic renal failure that may or may not lead to end-stage kidney disease (ESKD) anywhere between the second and seventh decade of life. In addition to other excellent laboratory tools that assist the clinician in reaching the correct diagnosis, the molecular analysis emerges as the gold standard in establishing the diagnosis in many cases of doubt due to equivocal findings that complicate the differential diagnosis. Recent work led to the description of candidate genetic modifiers which confer a variable risk for progressing to chronic renal failure when co-inherited on the background of a primary glomerulopathy. Finally, more families are still waiting to be studied and more genes to be mapped and cloned that are responsible for other forms of heritable hematuric diseases. The study of such genes and their protein products will likely shed more light on the structure and function of the glomerular filtration barrier and other important glomerular components. © The Author 2013. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved. 28 2946 2960 Cited By :27

Background: Medullary cystic kidney disease (MCKD) is an inherited interstitial nephritis, leading to endstage renal disease (ESRD) between the fourth and seventh decade of life. MCKD shares clinical and morphological features with nephronophthisis, although advances in molecular genetics have distinguished these 2 entities. Data regarding graft survival after kidney transplantation in MCKD patients are extremely limited. The aim of this study was to compare renal graft survival in transplanted MCKD1 and non-MCKD1 patients, to discover whether renal transplantation can be considered as an acceptable treatment for MCKD. Methods: Thirty-three transplanted patients with MCKD1 and 33 controls (transplanted due to other causes) were included in the study. Graft losses were considered censored for death. Graft survival was evaluated with the Kaplan-Meier method, and comparisons between groups were made by log-rank test. Cox regression analysis was used to estimate the effect of several variables on graft survival, and the chi-square test was used to compare groups of categorical data. Results: The 1-year cumulative graft survival rate for the MCKD1 group was 97%, while at 5 and 10 years it was 94% and 86%, respectively. For the control group, the respective values at years 1, 5 and 10 were 97%, 97% and 90%. Comparisons of graft survival rates between the 2 groups revealed no significant differences. Conclusions: Renal graft survival of transplanted MCKD1 patients was not shown to be inferior in comparison with that for patients undergoing transplants due to other causes. Therefore, it may represent a treatment of choice in MCKD1 patients with ESRD. © 2013 Società Italiana di Nefrologia. 26 793 798 Cited By :3

Background: The unfolded protein response (UPR) is a major signalling cascade acting in the quality control of protein folding in the endoplasmic reticulum (ER). The cascade is known to play an accessory role in a range of genetic and environmental disorders including neurodegenerative and cardiovascular diseases, diabetes and kidney diseases. The three major receptors of the ER stress involved with the UPR, i.e. IRE1 α, PERK and ATF6, signal through a complex web of pathways to convey an appropriate response. The emerging behaviour ranges from adaptive to maladaptive depending on the severity of unfolded protein accumulation in the ER however, the decision mechanism for the switch and its timing have so far been poorly understood.Results: Here, we propose a mechanism by which the UPR outcome switches between survival and death. We compose a mathematical model integrating the three signalling branches, and perform a comprehensive bifurcation analysis to investigate possible responses to stimuli. The analysis reveals three distinct states of behaviour, low, high and intermediate activity, associated with stress adaptation, tolerance, and the initiation of apoptosis. The decision to adapt or destruct can, therefore, be understood as a dynamic process where the balance between the stress and the folding capacity of the ER plays a pivotal role in managing the delivery of the most appropriate response. The model demonstrates for the first time that the UPR is capable of generating oscillations in translation attenuation and the apoptotic signals, and this is supplemented with a Bayesian sensitivity analysis identifying a set of parameters controlling this behaviour.Conclusions: This work contributes largely to the understanding of one of the most ubiquitous signalling pathways involved in protein folding quality control in the metazoan ER. The insights gained have direct consequences on the management of many UPR-related diseases, revealing, in addition, an extended list of candidate disease modifiers. Demonstration of stress adaptation sheds light to how preconditioning might be beneficial in manifesting the UPR outcome to prevent untimely apoptosis, and paves the way to novel approaches for the treatment of many UPR-related conditions. © 2013 Erguler et al. licensee BioMed Central Ltd. 7 Cited By :16

Alport syndrome (ATS) results from X-linked, COL4A5 mutations (85%) or from autosomal recessive homozygous or compound heterozygous COL4A3/A4 mutations (15%), associated with alternate thinning and thickening as well as splitting and lamellation of the glomerular basement membranes. In contrast, familial microhematuria with thin basement membranes is thought to result from heterozygous COL4A3/A4 mutations. This absolute separation may not always be true. Renal biopsies and molecular genetics were used to study microhematuric families in the Hellenic population we serve. The COL4A5 gene was studied by PCR and direct re-sequencing for new mutations, while PCR-RFLP was used to identify more carriers of known COL4A5 and COL4A3/A4 mutations. Molecular genetics in two undiagnosed microhematuric Cypriot families, revealed COL4A5 mutation P628L indicating X-linked ATS. Of nine males, seven developed end stage kidney disease (ESKD) between 31 and 56, while two are well at 51 and 57, exhibiting microhematuria and thin basement membrane nephropathy (TBMN). COL4A5 mutation G624D was also identified in six Greek families. Seventy five members had DNA tests and 37 proved positive. Four positive males developed ESKD at 61, 51, 50 and 39 years, while the remaining and all females showed only microhematuria. A literature search revealed eight papers with six similar hypomorphic COL4A5 mutations presenting as phenocopies of TBMN. In conclusion, X-linked COL4A5 ATS mutations produce a phenotypic spectrum with a) classical ATS with early onset ESKD, neurosensory deafness and ocular defects b) males with only ESKD and late deafness and c) males due to missense mutations, such as G624D and P628L that may only exhibit microhematuria, TBMN, mild chronic renal failure (CRF) or late onset ESKD. Consequently when investigating "benign familial hematuria" these and other similar X-linked COL4A5 mutations should also be searched for. 17 207 213 Cited By :8

Microscopic haematuria is the presenting symptom of several conditions, either heritable or acquired. A well-recognized familial condition is Alport syndrome, either of X-linked or autosomal recessive inheritance, as well as thin basement membrane nephropathy (TBMN) because of heterozygous collagen IV mutations. Even though microscopic haematuria of TBMN was long considered as a benign disease with excellent prognosis, more recent data suggest that development of chronic kidney disease (CKD) and even end-stage kidney disease (ESKD) is not a rare finding, perhaps owing to the cofounding role of modifier genes and other factors. Recent investigations in London and Cyprus culminated in the identification of another autosomal dominant condition that presents with microscopic haematuria because of heterozygous mutations in the CFHR5 gene, which apparently plays a pivotal role in the regulation of the alterative pathway of complement system, which constitutes a significant part of innate immunity in humans. Histologically, the hallmark observation is the isolated glomerular deposition of C3 complement in the absence of immune complexes. It is considered one of the C3 glomerulopathies, and it may or may not be accompanied by mild membranoproliferative glomerulonephritis. Interestingly, a single mutation has been identified so far, a duplication of exons 2-3 of the CFHR5 gene, and it has been described in patients of Greek-Cypriot descend only, perhaps originating on the Troodos mountains of Cyprus. Thus far, no patient with a mutation in this gene has been diagnosed in any other population. In Cyprus, it has been found in clusters of families in neighbouring villages in a total of 136 patients, and it constitutes a strong founder phenomenon. About 50% of patients over 50 years have progressed to CKD, and 14% of all patients progressed to ESKD. It is not quite well understood why males run a much higher risk to progress to CKD, compared to women. © 2013 Springer Science+Business Media New York. 734 189 196 Cited By :3

MicroRNAs (miRNAs) and copy number variations (CNVs) represent two classes of newly discovered genomic elements that were shown to contribute to genome plasticity and evolution. Recent studies demonstrated that miRNAs and CNVs must have co-evolved and interacted in an attempt to maintain the balance of the dosage sensitive genes and at the same time increase the diversity of dosage non-sensitive genes, contributing to species evolution. It has been previously demonstrated that both the number of miRNAs that target genes found in CNV regions as well as the number of miRNA binding sites are significantly higher than those of genes found in non-CNV regions. These findings raise the possibility that miRNAs may have been created under evolutionary pressure, as a mechanism for increasing the tolerance to genome plasticity. In the current study, we aimed in exploring the differences of miRNAs-CNV functional interactions between human and seven others species. By performing in silico whole genome analysis in eight different species (human, chimpanzee, macaque, mouse, rat, chicken, dog and cow), we demonstrate that miRNAs targeting genes located within CNV regions in humans have special functional characteristics that provide an insight into the differences between humans and other species. © 2013 Dweep et al. 8 Cited By :9

Familial hematuria (FH) is explained by at least four different genes (see below). About 50% of patients develop late proteinuria and chronic kidney disease (CKD). We hypothesized that MYH9/APOL1, two closely linked genes associated with CKD, may be associated with adverse progression in FH. Our study included 102 thin basement membrane nephropathy (TBMN) patients with three known COL4A3/COL4A4 mutations (cohort A), 83 CFHR5/C3 glomerulopathy patients (cohort B) with a single CFHR5 mutation and 15 Alport syndrome patients (cohort C) with two known COL4A5 mild mutations, who were categorized as "Mild" (controls) or "Severe" (cases), based on renal manifestations. E1 and S1 MYH9 haplotypes and variant rs11089788 were analyzed for association with disease phenotype. Evidence for association with "Severe" progression in CFHR5 nephropathy was found with MYH9 variant rs11089788 and was confirmed in an independent FH cohort, D (cumulative p value = 0.001, odds ratio = 3.06, recessive model). No association was found with APOL1 gene. Quantitative Real time PCR did not reveal any functional significance for the rs11089788 risk allele. Our results derive additional evidence supporting previous reports according to which MYH9 is an important gene per se, predisposing to CKD, suggesting its usefulness as a prognostic marker for young hematuric patients. © 2013 Voskarides et al. 8 Cited By :3

Heparin binding epidermal growth factor (HBEGF) is expressed in podocytes and was shown to play a role in glomerular physiology. MicroRNA binding sites on the 3′UTR of HBEGF were predicted using miRWalk algorithm and followed by DNA sequencing in 103 patients diagnosed with mild or severe glomerulopathy. A single nucleotide polymorphism, miRSNP C1936T (rs13385), was identified at the 3′UTR of HBEGF that corresponds to the second base of the hsa-miR-1207-5p seed region. When AB8/13 undifferentiated podocytes were transfected with miRNA mimics of hsa-miR-1207-5p, the HBEGF protein levels were reduced by about 50%. A DNA fragment containing the miRSNP allele-1936C was cloned into the pMIR-Report Luciferase vector and co-transfected with miRNA mimics of hsa-miR-1207-5p into AB8/13 podocytes. In agreement with western blot data, this resulted in reduced luciferase expression demonstrating the ability of hsa-miR-1207-5p to directly regulate HBEGF expression. On the contrary, in the presence of the miRSNP 1936T allele, this regulation was abolished. Collectively, these results demonstrate that variant 1936T of this miRSNP prevents hsa-miR-1207-5p from down-regulating HBEGF in podocytes. We hypothesized that this variant has a functional role as a genetic modifier. To this end, we showed that in a cohort of 78 patients diagnosed with CFHR5 nephropathy (also known as C3-glomerulopathy), inheritance of miRSNP 1936T allele was significantly increased in the group demonstrating progression to chronic renal failure on long follow-up. No similar association was detected in a cohort of patients with thin basement membrane nephropathy. This is the first report associating a miRSNP as genetic modifier to a monogenic renal disorder. © 2012 Papagregoriou et al. 7 Cited By :30

CY-NiUL UCY-LIB PLATANIS RC904.D57 2012 $7 10360525 000344045 ΔΕΛΤΑΣ, ΚΩΝΣΤΑΝΤΙΝΟΣ In Library ID: 91 hbk. 20120615d2012 y0engy010503 ba col. ill. 25 cm. Includes references ( Kidneys Diseases Diagnosis 0 CY University of Cyprus 20120615 AACR-2 292

The X-linked Alport syndrome (ATS) is caused by mutations in COL4A5 and exhibits a widely variable expression. Usually ATS is heralded with continuous microhematuria which rapidly progresses to proteinuria, hypertension and chronic or end-stage renal disease (ESRD) by adolescence, frequently accompanied by sensorineural deafness and ocular complications. Milder forms of ATS also exist. We studied 42 patients (19M, 23F) of nine Hellenic families suspected clinically of X-linked ATS who presented with marked phenotypic heterogeneity. We identified mutations in COL4A5 in six families. Two males with nonsense mutation E228X reached ESRD by ages 14 and 18. Frameshift mutation 2946delT followed the same course with early onset renal involvement and deafness. However, two males with the milder missense mutation G624D, reached ESRD after 39 years and one patient showed thin basement membrane nephropathy (TBMN). Another 5/8 affected males with missense mutation P628L also developed ESRD between 30 and 57 years, while three exhibit only mild chronic renal failure (CRF). The data support previous findings that certain mutations are associated with milder phenotypes and confirm that mutation G624D may be expressed as TBMN with familial hematuria. Similar conclusions apply for missense mutation P628L. Interestingly, mutations G624D and P628L are near the 12th natural interruption of COL4A5 triple helical domain, which may explain the milder phenotype. © 2011 John Wiley & Sons A/S. 81 240 248

Background: RET germline mutations predispose to the development of inherited cancer syndrome multiple endocrine neoplasia type 2 (MEN2). Several variants of the RET proto-oncogene including G691S and S904S have been suggested to act as genetic modifiers at the age of onset of MEN2. Aim: The aim of this study is to characterize clinically and molecularly 7 Cypriot patients with familial medullary thyroid carcinoma (FMTC) and 1 with MEN2A and also to determine the allelic frequencies of the RET variants G691S and S904S. Subjects and methods: Seven probands from FMTC families and 1 from MEN2A were screened for the presence of RET mutations and the G691S and S904S variants. Additionally, 226 healthy Cypriote, who served as controls were analysed in an attempt to compare the frequencies of G691S and S904S RET variants to those observed in the 8 patients. Results: The clinical diagnosis of the probands was based on clinical presentation and supported with biochemical findings. The germline C618R mutation of exon 10 was identified in all 8 probands and in 15 relatives from 7 different families. No significant difference in the G691S/S904S variants allele frequencies between patients (4/16 or 25%) and controls (124/452 or 27.4%) was found. Conclusions: Mutational screening of the RET gene identified a common mutation (C618R) in all 8 (7 FMTC and 1 MEN2A) unrelated Cypriot patients which may be explained by a founder effect. Additionally, no association of the G691S/S904S variants was linked with the disease. ©2011, Editrice Kurtis. 34 764 769 Cited By :5

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Aims: To investigate clinically and genetically all the distal renal tubular acidosis (dRTA) cases in Cyprus, to study one more family from Greece and to perform the first dRTA prenatal diagnosis. We also tried to find any association with sensorineural hearing loss (SNHL) onset and particular mutations. Methods: Nine dRTA families from Cyprus and one from Greece were analyzed for mutations in ATP6V1B1 gene by DNA resequencing and PCR-RFLPs. Clinical diagnosis was performed by standard criteria. Prenatal diagnosis was performed for one Cypriot family. Results: Results show that 7/9 dRTA cases in Cyprus are caused by 229+1G>T and R157C founder mutations in ATP6V1B1 gene. 229+1G>T mutation was estimated to be older than 400 years. No genotype- phenotype correlation was found with SNHL. A known (L81P) and a novel mutation (912delT) were found in the Greek family. Prenatal diagnosis was performed for one Cypriot family, after parents' demand, showing that the embryo was a heterozygous carrier. Conclusion: Existence of only two ATP6V1B1 mutations in the Cypriot population is a diagnostic advantage. The age of onset of SNHL varies in our patients and probably is not related to ATP6V1B1 genotypes. Effective therapy for most of the syndrome symptoms is not satisfactory for some parents who choose prenatal diagnosis to ensure their child's health. Copyright © 2010 S. Karger AG, Basel. 117 c206 c212 Cited By :6

Mutations in the genes coding for the proα1 and proα2 chains of type I procollagen have been found in many patients with osteogenesis imperfecta (OI), a heritable disorder of connective tissue. The severity of the disease varies between families and even among members of the same family. This phenotypic variability covers a spectrum extending from very mild forms that cannot be easily detected to perinatally lethal forms. One explanation for this phenotypic variability is the nature of the mutation in the type I procollagen genes. Another explanation is mosaicism. Here we report on 2 families with propositi who have OI, whereas their mothers had a milder form of the disease. In one family, the molecular defect was previously shown to be a substitution of α1904 by cysteine [Constantinou et al., 1990]. The biochemical phenotype was characterized by significant post-translational over-modification of the mutated type 1 collagen molecules which also had a 3-4°C decrease in their thermal unfolding. Also, secretion of the procollagen into the culture media was delayed. In the second family, the proposita's muscle fibroblasts synthesized and secreted type I procollagen molecules that were highly over-modified along the entire length of their triple-helical domain. Cells from the mother also synthesized normal and over-modified protein, although the amount of over-modified protein was less than that synthesized by her daughter's cells. The exact molecular defect has not yet been defined. The simplest explanation for the phenotypic variability seen within these 2 families is that the mothers of the propositi are mosaic for their respective mutations so that not all of their somatic cells produce abnormal type I procollagen. Hence, one additional explanation for the phenotypic variability in OI is the abundance of the mutated allele or the degree of mosaicism in the patient's population of cells so that the first affected individual in a family may be mildly affected by a mutation which in a heterozygous form is potentially lethal in his or her offspring. 45 246 251 Cited By :14

Clear cell renal-cell carcinoma (ccRCC) represents the most common RCC subtype, being exceptionally resistant to therapy and responding poorly to radiotherapy, hormonal therapy and chemotherapy1; t...

Significant variation in the course of autosomal dominant polycystic kidney disease (ADPKD) within families suggests the presence of effect modifiers. Recent studies of the variation within families harboring PKD1 mutations indicate that genetic background may account for 32 to 42% of the variance in estimated GFR (eGFR) before ESRD and 43 to 78% of the variance in age at ESRD onset, but the genetic modifiers are unknown. Here, we conducted a high-throughput single-nucleotide polymorphism (SNP) genotyping association study of 173 biological candidate genes in 794 white patients from 227 families with PKD1. We analyzed two primary outcomes: (1) eGFR and (2) time to ESRD (renal survival). For both outcomes, we used multidimensional scaling to correct for population structure and generalized estimating equations to account for the relatedness among individuals within the same family. We found suggestive associations between each of 12 SNPs and at least one of the renal outcomes. We genotyped these SNPs in a second set of 472 white patients from 229 families with PKD1 and performed a joint analysis on both cohorts. Three SNPs continued to show suggestive/significant association with eGFR at the Dickkopf 3 (DKK3) gene locus no SNPs significantly associated with renal survival. DKK3 antagonizes Wnt/β-catenin signaling, which may modulate renal cyst growth. Pending replication, our study suggests that genetic variation of DKK3 may modify severity of ADPKD resulting from PKD1 mutations. Copyright © 2010 by the American Society of Nephrology. 21 1510 1520 Cited By :31

8 páginas, 8 figuras, 1 tabla -- PAGS nros. 794-801, Background Complement is a key component of the innate immune system, and variation in genes that regulate its activation is associated with renal and other disease. We aimed to establish the genetic basis for a familial disorder of complement regulation associated with persistent microscopic haematuria, recurrent macroscopic haematuria, glomerulonephritis, and progressive renal failure. Methods We sought patients from the West London Renal and Transplant Centre (London, UK) with unusual renal disease and affected family members as a method of identification of new genetic causes of kidney disease. Two families of Cypriot origin were identified in which renal disease was consistent with autosomal dominant transmission and renal biopsy of at least one individual showed C3 glomerulonephritis. A mutation was identified via a genome-wide linkage study and candidate gene analysis. A PCR-based diagnostic test was then developed and used to screen for the mutation in population-based samples and in individuals and families with renal disease. Findings Occurrence of familial renal disease cosegregated with the same mutation in the complement factor H-related protein 5 gene (CFHR5). In a cohort of 84 Cypriots with unexplained renal disease, four had mutation in CFHR5. Overall, we identified 26 individuals with the mutation and evidence of renal disease from 11 ostensibly unrelated kindreds, including the original two families. A mutant CFHR5 protein present in patient serum had reduced affinity for surface-bound complement. We term this renal disease CFHR5 nephropathy. Interpretation CFHR5 nephropathy accounts for a substantial burden of renal disease in patients of Cypriot origin and can be diagnosed with a specific molecular test. The high risk of progressive renal disease in carriers of the CFHR5 mutation implies that isolated microscopic haematuria or recurrent macroscopic haematuria should not be regarded as a benign finding in individuals of Cypriot descent, DPG is supported by the UK Medical Research Council and EGdJ and MCP are supported by the Wellcome Trust. Additional support was provided by the UK National Institute for Health Research Biomedical Research Centre Funding Scheme and the Cyprus Research Promotion MCP is a Wellcome Trust Senior Fellow in Clinical Science (WT082291MA) and GdJ is funded by this fellowship. CD is supported by the Cyprus Research Promotion Foundation through grants ENIΣX/0505/02 and ENIΣX/0308/08. Additional support was obtained from the UK National Institute for Health Research Biomedical Research Centre Funding Scheme. PHM is supported by the EU large scale collaborative project Metoxia, the St Peter’s Trust, and a Senior Investigator Award from the UK National Institute for Health Research

14(4): 236-240. Micro RNAs are evolutionarily conserved, single stranded molecules of about 22 nucleotides in length and function post-transcriptionally by partial binding (partial complementarity) to the mRNA of genes. Binding of a specific miRNA to its target on an mRNA can inhibit its expression by a variety of mechanisms. Although the most common mechanism is translational repression as a result of miRNA binding to the 3'UTR of an mRNA, mechanisms involving mRNA degradation and destabilization have also been described. Micro RNAs are currently considered as "master regulators" of gene expression. Since a single miRNA can bind and consequently regulate the expression of more than 100 different transcripts it has been estimated that miRNAs may be able to regulate up to 30% of the protein-coding genes in the human genome. As a result, miRNAs receive widespread attention on their potential role in complicated biological processes and multifactorial diseases. In this review we are discussing the biogenesis of miRNAs, their mode of action as well as their role in human diseases through genetic variations on their target sites. Hippokratia 2010 14 236 240 Cited By :60

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Context.-Cystic diseases of the kidney are a very heterogeneous group of renal inherited conditions, with more than 33 genes involved and encompassing Xlinked, autosomal dominant, and autosomal recessive inheritance. Although mostly monogenic with mendelian inheritance, there are clearly examples of oligogenic inheritance, such as 3 mutations in 2 genes, while the existence of genetic modifiers is perhaps the norm, based on the extent of variable expressivity and the broad spectrum of symptoms. Objectives.-To present in the form of a mini review the major known cystic diseases of the kidney for which genes have been mapped or cloned and characterized, with some information on their cellular and molecular biology and genetics, and to pay special attention to commenting on the issues of molecular diagnostics, in view of the genetic and allelic heterogeneity. Data Sources.-We used major reviews that make excellent detailed presentation of the various diseases, as well as original publications. Conclusions.-There is already extensive genetic heterogeneity in the group of cystic diseases of the kidney however, there are still many more genes awaiting to be discovered that are implicated or mutated in these diseases. In addition, the synergism and interaction among this repertoire of gene products is largely unknown, while a common unifying aspect is the expression of nearly all of them at the primary cilium or the basal body. A major interplay of functions is anticipated, while mutations in all converge in the unifying phenotype of cyst formation. 134 569 582 Cited By :20