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Background: Autosomal recessive polycystic kidney disease (ARPKD) is a genetically inherited pediatric disorder. It is caused by a mutation in the PKHD1 gene located on chromosome 6. The predominant phenotype is characterized by early-onset bilateral enlarged kidneys, as well as fibrocystic changes in the kidney and liver. Fetuses or infants usually present with Potter syndrome, and they are more likely to develop severe renal insufficiency. Generally, patients die perinatally or in infancy. Liver involvement has been reported in adults with ARPKD who have survived the neonatal period and childhood. However, renal involvement is rarely expected in adulthood. The case is being presented for its clinical rarity, in addition to emphasize the critical role of NGS approaches in diagnosis. Case presentation: We hereby describe a 33-year-old female with adult-onset proteinuria and nephromegaly. She had a rare homozygous missense mutation of the PKHD1 gene with autosomal recessive inheritance. The proband has consanguineous heterozygote parents. The mutation was identified by whole-exome sequencing, and the results were confirmed by segregation analysis. Conclusion: Here, we reported a thorough literature review of late-onset autosomal recessive polycystic kidney disease. Furthermore, we explored the importance of genetic work-up in families with genetic disorders and consanguineous marriages, particularly in underdeveloped countries. [ABSTRACT FROM AUTHOR]

Background: Prenatal ultrasound findings of fetal bilateral echogenic kidneys accompanied by oligohydramnios can be highly stressful for both pregnant women and physicians. The diversity of underlying causes makes it challenging to confirm a prenatal diagnosis, predict postnatal outcomes, and counsel regarding recurrence risks in future pregnancies. Case Presentation: We report two cases of abnormal fetal echogenic kidneys with oligohydramnios detected in the early third trimester. Autosomal recessive polycystic kidney disease (ARPKD), a rare genetic syndrome, was initially suspected in both cases. However, postnatal diagnoses differed: the first case was confirmed as glomerulocystic kidney disease (GCKD) through renal pathology, while the second case was diagnosed as ARPKD with a compound heterozygous likely pathogenic PKHD1 mutation. Conclusion: Prenatal diagnosis of fetal echogenic kidneys with oligohydramnios should prioritize accurate diagnosis. Given the differences in the clinical spectrum, GCKD should be considered a differential diagnosis for this condition, particularly ARPKD. This study highlights the importance and benefits of molecular diagnosis and postnatal renal pathology for precise diagnosis and effective counseling. [ABSTRACT FROM AUTHOR]

Nagashima-type palmoplantar keratosis (NPPK) is a relatively common autosomal recessive dermatosis characterized by well-defined diffuse erythema and non-destructive hyperkeratosis on the palmoplantar areas, with swelling and whitening when exposed to water. The pathogenesis of NPPK can be attributable to altered structure and function of SERPINB7, environmental factors, barrier dysfunction and inflammatory response. There is no specific and standardized therapy for this disorder. Topical treatment is primary therapy although systemic drugs or surgery can be used for severe cases. Gentamicin, a targeted therapy for the disease, has shown some potential, but more clinical studies are still needed to verify its efficacy and safety. The aim of this review is to summarize the causative gene, pathogenesis and therapeutic strategies of NPPK. [ABSTRACT FROM AUTHOR]

Background/aim: Autosomal recessive polycystic kidney disease is an inherited kidney disease. This study aims to detect rare and common DNA variants of the PKHD1 gene using next-generation sequencing (NGS) and to classify them in terms of being pathogenic according to The American College of Medical Genetics and Genomics. Materials and methods: NGS analysis was performed on the DNA of 304 patients who were referred to Ege University Molecular Medicine Laboratory with suspected polycystic kidney disease. Results: As a result, a total of 82 different DNA variants, 16 of which were novel, were detected. The breakdown of the variants found is as follows: 73 (89.02%) were missense variants, six (7.32%) nonsense variants, two (2.44%) frameshift deletions, and one (1.22%) nonframeshift deletion. According to The American College of Medical Genetics and Genomics classification of these variants, 26 were benign (Class 5), two were likely benign (Class 4), 36 were of uncertain significance (Class 3), and nine were likely pathogenic (Class 2), nine of which are pathogenic variants (Class 1). Heterozygosity was found in 39 (63.9%) patients, homozygosity in six (9.8%) patients, compound heterozygosity in 12 (19.7%) patients, and complex genotype in four (6.6%) patients in which variants in Class 1, Class 2 and Class 3 were determined according to ACMG classification. When the exon distributions of the DNA variants detected in the PKHD1 gene were analyzed, the most common exons of the DNA variant are exon 32 (n = 9), exon 58 (n = 8), exon 67 (n = 6), exon 61 (n = 5), 30 exons (n = 4). Conclusion: This fast and economical molecular diagnostic approach will provide a reliable prenatal diagnostic option, enabling definitive disease diagnosis and the identification of carriers. [ABSTRACT FROM AUTHOR]

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Background: To investigate whether the novel mutation of PKHD1 could cause polycystic kidney disease by affecting splicing with a recessive inheritance pattern. Methods: A nonconsanguineous Chinese couple with two recurrent pregnancies showed fetal enlarged echogenic polycystic kidney and oligoamnios were recruited. Pedigree WES, minigene splicing assay experiment and following bioinformatics analysis were performed to verify the effects, and inheritance pattern of diseasing-causing mutations. Results: WES revealed that both fetuses were identified as carrying the same novel mutation c.3592_3628 + 45del, p.? and c.11207 T>C, p.(Ile3736Thr) in the PKHD1 gene (NM_138694.4), which inherited from the father and mother respectively. Both bioinformatic method prediction and minigene splicing assay experience results supported the mutation c.3592_3628 + 45del, p.? affects the splicing of the PKHD1 transcript, resulting in exon 31 skipping. Another missense mutation c.11207 T>C, p.(Ile3736Thr) has a low frequency in populations and is predicted to be deleterious by bioinformatic methods. Conclusion: These findings provide a direct clinical and functional evidence that the truncating mutations of the PKHD1 gene could lead to more severe phenotypes, and cause ARPKD as a homozygous or compound heterozygous pattern. Our study broadens the variant spectrum of the PKHD1 gene and provides a basis for genetic counseling and diagnosis of ARPKD. [ABSTRACT FROM AUTHOR]

Cowden syndrome (CS) is a rare autosomal dominant genodermatosis caused by a heterozygous germline mutation in the PTEN gene, found in nearly 80% of cases. It is characterized by multiple benign hamartomas which manifest across various organs. This condition is further distinguished by its association with macrocephaly, facial trichilemmomas, acral keratoses, papillomatous papules, and a heightened susceptibility to certain malignant neoplasms, particularly affecting the thyroid, endometrium, and the breast (OMIM no. 58350). In this report, we detail the case of an Indian patient presenting with macrocephaly and multiple blackish pigmented areas on the face, alongside several small papules on the dorsum of the hands, and the presence of gastric and duodenal polyps, among other symptoms. Genetic analysis through Sanger sequencing of the PTEN gene revealed a heterozygous nonsense pathogenic variant (ENST00000371953.8: c.388C > T, p.Arg130Ter), thereby confirming a CS diagnosis. The report encompasses a comprehensive review of the existing literature, emphasizing the significance of genetic evaluation and discussing the intricacies of managing patients diagnosed with CS. [ABSTRACT FROM AUTHOR]

Serving as the cell's sensory antennae, primary cilia are linked to numerous human genetic diseases when they malfunction. DZIP1L, identified as one of the genetic causes of human autosomal recessive polycystic kidney disease (ARPKD), is an evolutionarily conserved ciliary basal body protein. Although it has been reported that DZIP1L is involved in the ciliary entry of PKD proteins, the underlying mechanism remains elusive. Here, an uncharacterized role of DZIP1L is reported in modulating the architecture and function of transition fibers (TFs), striking ciliary base structures essential for selective cilia gating. Using C. elegans as a model, C01G5.7 (hereafter termed DZIP‐1) is identified as the sole homolog of DZIP1L, which specifically localizes to TFs. While DZIP‐1 or ANKR‐26 (the ortholog of ANKRD26) deficiency shows subtle impact on TFs, co‐depletion of DZIP‐1 and ANKR‐26 disrupts TF assembly and cilia gating for soluble and membrane proteins, including the ortholog of ADPKD protein polycystin‐2. Notably, the synergistic role for DZIP1L and ANKRD26 in the formation and function of TFs is highly conserved in mammalian cilia. Hence, the findings illuminate an evolutionarily conserved role of DZIP1L in TFs architecture and function, highlighting TFs as a vital part of the ciliary gate implicated in ciliopathies ARPKD. [ABSTRACT FROM AUTHOR]

Background: Autosomal recessive polycystic kidney disease (ARPKD) is a rare inherited cystic disease characterized by bilateral renal cyst formation and congenital liver fibrosis. Cardiovascular disorders such as noncompaction of ventricular myocardium (NVM) have not been reported with ARPKD. Case presentation: A 5-month-old girl was examined after presenting with a fever and turbid urine for one day and was diagnosed as urinary tract infection. Urinary ultrasound showed multiple round, small cysts varying in size in both kidneys. Genetic testing revealed two heterozygous mutations and one exon deletion in the polycystic kidney and hepatic disease 1 gene, indicating a diagnosis of ARPKD. During hospitalization, she was found to have chronic heart failure after respiratory tract infection, with an ejection fraction of 29% and fraction shortening of 13%. When the patient was 15 months old, it was found that she had prominent trabeculations and deep intertrabecular recesses with the appearance of blood flow from the ventricular cavity into the intertrabecular recesses by echocardiography. The noncompaction myocardium was 0.716 cm and compaction myocardium was 0.221 cm (N/C = 3.27), indicating a diagnosis of NVM. Liver and kidney function remained normal during four-year follow-up. Conclusions: This is the first report of NVM in a patient with ARPKD. It is unsure if the coexistence of NVM and ARPKD is a coincidence or they are different manifestations of ciliary dysfunction in the heart and kidneys. [ABSTRACT FROM AUTHOR]

Humans are predisposed to gout because they lack uricase that converts uric acid to allantoin. Rodents have uricase, resulting in low basal serum uric acid. A uricase inhibitor raises serum uric acid in rodents. There were two aims of the study in polycystic kidney disease (PKD): 1) to determine whether increasing serum uric acid with the uricase inhibitor, oxonic acid, resulted in faster cyst growth and 2) to determine whether treatment with the xanthine oxidase inhibitor, oxypurinol, reduced the cyst growth caused by oxonic acid. Orthologous models of human PKD were used: PCK rats, a polycystic kidney and hepatic disease 1 (Pkhd1) gene model of autosomal recessive PKD (ARPKD) and Pkd1RC/RC mice, a hypomorphic Pkd1 gene model. In PCK rats and Pkd1RC/RC mice, oxonic acid resulted in a significant increase in serum uric acid, kidney weight, and cyst index. Mechanisms of increased cyst growth that were investigated were proinflammatory cytokines, the inflammasome, and crystal deposition in the kidney. Oxonic acid resulted in an increase in proinflammatory cytokines in the serum and kidney in Pkd1RC/RC mice. Oxonic acid did not cause activation of the inflammasome or uric acid crystal deposition in the kidney. In Pkd1RC/RC male and female mice analyzed together, oxypurinol decreased the oxonic acid-induced increase in cyst index. In summary, increasing serum uric acid by inhibiting uricase with oxonic acid results in an increase in kidney weight and cyst index in PCK rats and Pkd1RC/RC mice. The effect is independent of inflammasome activation or crystal deposition in the kidney. NEW & NOTEWORTHY: This is the first reported study of uric acid measurements and xanthine oxidase inhibition in polycystic kidney disease (PKD) rodents. Raising serum uric acid with a uricase inhibitor resulted in increased kidney weight and cyst index in Pkd1RC/RC mice and PCK rats, elevated levels of proinflammatory cytokines in the serum and kidney in Pkd1RC/RC mice, and no uric acid crystal deposition or activation of the caspase-1 inflammasome in the kidney. [ABSTRACT FROM AUTHOR]

Polycystic liver disease (PLD) is a rare condition observed in three genetic diseases, including autosomal dominant polycystic liver disease (ADPLD), autosomal dominant polycystic kidney disease (ADPKD), and autosomal recessive polycystic kidney disease (ARPKD). PLD usually does not impair liver function, and advanced PLD becomes symptomatic when the enlarged liver compresses adjacent organs or increases intra-abdominal pressure. Currently, the diagnosis of PLD is mainly based on imaging, and genetic testing is not required except for complex cases. Besides, genetic testing may help predict patients' prognosis, classify patients for genetic intervention, and conduct early treatment. Although the underlying genetic causes and mechanisms are not fully understood, previous studies refer to primary ciliopathy or impaired ciliogenesis as the main culprit. Primarily, PLD occurs due to defective ciliogenesis and ineffective endoplasmic reticulum quality control. Specifically, loss of function mutations of genes that are directly involved in ciliogenesis, such as Pkd1, Pkd2, Pkhd1, and Dzip1l, can lead to both hepatic and renal cystogenesis in ADPKD and ARPKD. In addition, loss of function mutations of genes that are involved in endoplasmic reticulum quality control and protein folding, trafficking, and maturation, such as PRKCSH, Sec63, ALG8, ALG9, GANAB, and SEC61B, can impair the production and function of polycystin1 (PC1) and polycystin 2 (PC2) or facilitate their degradation and indirectly promote isolated hepatic cystogenesis or concurrent hepatic and renal cystogenesis. Recently, it was shown that mutations of LRP5, which impairs canonical Wnt signaling, can lead to hepatic cystogenesis. PLD is currently treated by somatostatin analogs, percutaneous intervention, surgical fenestration, resection, and liver transplantation. In addition, based on the underlying molecular mechanisms and signaling pathways, several investigational treatments have been used in preclinical studies, some of which have shown promising results. This review discusses the clinical manifestation, complications, prevalence, genetic basis, and treatment of PLD and explains the investigational methods of treatment and future research direction, which can be beneficial for researchers and clinicians interested in PLD. [ABSTRACT FROM AUTHOR]

Autosomal recessive polycystic kidney disease is a renal development anomaly characterized by cystic transformation in renal parenchyma. ARPKD is more common in children. We present the case of a premature newborn, female, 36-37 weeks gestation, small for gestational age (SGA) originating from a completely unmonitored pregnancy, diagnosed upon admission to the clinic with unilateral multicystic dysplastic kidney. The condition complicated by a urinary tract infection with E. coli. This newborn displayed no clinical symptoms, was carefully monitored during hospitalization, and received antibiotic treatment. Antenatal ultrasound screening can aid in the early diagnosis of congenital anomalies and determining the appropriate course of action. [ABSTRACT FROM AUTHOR]

Autosomal recessive polycystic kidney disease (ARPKD) is often associated with hepatobiliary disease in the form of hepatic fibrosis and/or Caroli disease. Combined liver–kidney transplantation (CLKT) is a transplant modality of choice in children with both end-stage renal disease (ESRD) and severe hepatic disease. However, there is no consensus on whether children with ARPKD-associated ESRD without severe hepatic disease can be treated with isolated kidney transplantation (KT) without the need for CLKT. We retrospectively studied the efficacy of isolated KT in children with ARPKD without severe hepatic disease, and followed the course of hepatic disease post KT. This is a single-center study of three children with ARPKD and ESRD who underwent isolated KT. None of them had severe hepatic disease at the time of KT. All children were clinically diagnosed with ARPKD in the immediate postnatal period. All had hepatic fibrosis of varying degrees and two had intrahepatic biliary duct (IHBD) dilatation. None had gastrointestinal (GI) bleed, portal hypertension or cholangitis. Two children had preemptive KT. Pre-transplant unilateral or bilateral native nephrectomy were performed for two children, and one underwent unilateral native nephrectomy at the time of KT. The median creatinine clearance at a median post-KT follow-up of 24 months was 60.3 mL/min/1.73 m2. The two-year graft and patient survival were both 100%. Post KT, all three patients continued to demonstrate evidence of hepatic fibrosis and IHBD on sonogram; however, none of them were either evaluated for or required liver transplantation given normal synthetic liver function and absence of portal hypertension or other severe hepatobiliary disease. There were no adverse events observed such as cholangitis, GI bleed, or multiorgan failure. Hence, an excellent short-term graft and patient survival was demonstrated in this study of children with ARPKD and mild to moderate hepatic disease who received isolated KT. Long-term follow-up and larger studies are important to assess the efficacy of isolated KT in this subset of children with ARPKD. [ABSTRACT FROM AUTHOR]

Background/Aims: The PCK rat model of polycystic kidney disease is characterized by the progressive development of renal medullary cysts. Here, we evaluated the suitability of high resolution ultrasonography (HRU) to assess the kidney and cyst volume in PCK rats, testing three different ultrasound image analysis methods, and correlating them with kidneys weights and histological examinations. Methods: After inducing anesthesia, PCK rats (n=18) were subjected to HRU to visualize the kidneys, to perform numeric and volumetric measurements of the kidney and any cysts observed, and to generate 3-dimensional images of the cysts within the kidney parenchyma. Results: HRU provided superior information in comparison to microscopic analysis of stained kidney sections. HRU-based kidney volumes correlated strongly with kidney weights (R2=0.809; P<0.0001). Conclusion: HRU represents a useful diagnostic tool for kidney and cyst volume measurements in PCK rats. Sequential HRU examinations may be useful to study the effect of drugs on cyst growth without the need to euthanize experimental animals. [ABSTRACT FROM AUTHOR]

Renal cystic diseases (RCDs) can arise from utero to early adulthood and present with a variety of symptoms including renal, hepatic, and cardiovascular manifestations. It is well known that common RCDs such as autosomal polycystic kidney disease and autosomal recessive kidney disease are linked to genes such as PKD1 and PKHD1, respectively. However, it is important to investigate the genetic pathophysiology of how these gene mutations lead to clinical symptoms and include some of the less-studied RCDs, such as autosomal dominant tubulointerstitial kidney disease, multicystic dysplastic kidney, Zellweger syndrome, calyceal diverticula, and more. We plan to take a thorough look into the genetic involvement and clinical sequalae of a number of RCDs with the goal of helping to guide diagnosis, counseling, and treatment. [ABSTRACT FROM AUTHOR]

Autosomal recessive polycystic kidney disease is an early onset inherited hepatorenal disorder affecting around 1 in 20,000 births with no approved specific therapies. The disease is almost always caused by variations in the polycystic kidney and hepatic disease 1 gene, which encodes fibrocystin (FC), a very large, single‐pass transmembrane glycoprotein found in primary cilia, urine and urinary exosomes. By comparison to proteins involved in autosomal dominant PKD, our structural and molecular understanding of FC has lagged far behind such that there are no published experimentally determined structures of any part of the protein. Bioinformatics analyses predict that the ectodomain contains a long chain of immunoglobulin‐like plexin‐transcription factor domains, a protective antigen 14 domain, a tandem G8‐TMEM2 homology region and a sperm protein, enterokinase and agrin domain. Here we review current knowledge on the molecular function of the protein from a structural perspective. [ABSTRACT FROM AUTHOR]

Introduction: The PKHD1 (Polycystic Kidney and Hepatic Disease 1) gene is essential for producing fibrocystin or polyductin, which is crucial in various cellular functions. Mutations in PKHD1 have been found to be involved in the development and progression of colorectal cancer (CRC). Along with APC, TP53, and KRAS, PKHD1 is one of the most frequently mutated genes in CRC. PKHD1 expression is governed by the Wnt/PCP pathway, often dysregulated in CRC. Targeting this pathway, crucial for CRC progression, could unveil potential therapeutic strategies for colon cancer treatment. Methods: This study examined an in-house dataset of 3702 colon cancer samples, analyzing mutation landscapes, clinical features, tumor mutational burden (TMB), microsatellite instability (MSI), and chromosomal instability (CIN) score. For the survival analysis of PKHD1 patients, survival data of 436 colon adenocarcinoma samples were obtained from TCGA dataset. Additionally, 433 samples from TCGA with RNA-seq data were used for the assessment of immune cell infiltration and gene set enrichment analysis. Results: Polycystic Kidney and Hepatic Disease 1 mutation was detected in 424 colon cancer patients from our in-house cohort and was associated with increased TMB, higher MSI, and lower CIN score. Importantly, within the TCGA dataset, PKHD1 mutations were identified as an independent prognostic factor, not merely correlated with established prognostic biomarkers, and were associated with poorer overall survival outcomes. In terms of immune response, these mutations correlated with increased enrichment scores for 12 immune cell types, including B cell plasma, macrophages, and naive CD4+ T cells. Additionally, interferon alpha and interferon-gamma gene sets were significantly down-regulated in patients with PKHD1 mutations (FDA q-value<0.1). Conclusions: Overall, these findings suggest that PKHD1 may be a potential biomarker for the prognosis of colon cancer and provide some insight for personalized immunotherapy. [ABSTRACT FROM AUTHOR]

Thurston syndrome ( oral ‑ facial ‑ digital syndromes [OFDS] Type V) is characterized by median cleft lip, postaxial polydactyly of hands and feet, and other oral manifestations. It is one of the OFDS described earlier in the literature. It is commonly seen in individuals of Indian origin and has autosomal recessive inheritance. This article presents two Indian female siblings with median upper lip cleft associated with postaxial hexadactyly of both hands. Rarely have such cases been reported by any author. Majority of the previously reported cases are males. This is the first case report of female siblings with Thurston syndrome. [ABSTRACT FROM AUTHOR]

Autosomal recessive polycystic kidney disease (ARPKD; MIM#263200) is a severe, hereditary, hepato-renal fibrocystic disorder that leads to early childhood morbidity and mortality. Typical forms of ARPKD are caused by pathogenic variants in the PKHD1 gene, which encodes the fibrocystin/polyductin (FPC) protein. MYC overexpression has been proposed as a driver of renal cystogenesis, but little is known about MYC expression in recessive PKD. In the current study, we provide the first evidence that MYC is overexpressed in kidneys from ARPKD patients and confirm that MYC is upregulated in cystic kidneys from cpk mutant mice. In contrast, renal MYC expression levels were not altered in several Pkhd1 mutant mice that lack a significant cystic kidney phenotype. We leveraged previous observations that the carboxy-terminus of mouse FPC (FPCCTD) is proteolytically cleaved through Notch-like processing, translocates to the nucleus, and binds to double stranded DNA, to examine whether the FPC-CTD plays a role in regulating MYC/Myc transcription. Using immunofluorescence, reporter gene assays, and ChIP, we demonstrate that both human and mouse FPC-CTD can localize to the nucleus, bind to the MYC/Myc P1 promoter, and activate MYC/Myc expression. Interestingly, we observed species-specific differences in FPC-CTD intracellular trafficking. Furthermore, our informatic analyses revealed limited sequence identity of FPC-CTD across vertebrate phyla and database queries identified temporal differences in PKHD1/Pkhd1 and CYS1/Cys1 expression patterns in mouse and human kidneys. Given that cystin, the Cys1 gene product, is a negative regulator of Myc transcription, these temporal differences in gene expression could contribute to the relative renoprotection from cystogenesis in Pkhd1-deficient mice. Taken together, our findings provide new mechanistic insights into differential mFPC-CTD and hFPCCTD regulation of MYC expression in renal epithelial cells, which may illuminate the basis for the phenotypic disparities between human patients with PKHD1 pathogenic variants and Pkhd1-mutant mice. [ABSTRACT FROM AUTHOR]

Objective: Chromosomal microarray (CMA) is primarily used for the diagnosis of chromosomal deletions and duplications that have a direct phenotype based solely on that copy number variation (CNV) without other genetic changes. However, CNVs that contain a gene associated with a recessive disorder confer risk for that disorder should a second pathogenic variant be present in the other copy of the gene. The study aimed to propose a protocol to be considered for follow up testing after the detection of CNV containing an autosomal recessive gene on prenatal sample via chromosomal microarray. Methods: We present 5 cases involving prenatal diagnosis where CMA identified changes in an autosomal recessive gene conferring carrier status and discuss management of this finding. Results: Algorithm of selecting different diagnostic genetic testing after the detection of CNV containing an autosomal recessive gene on prenatal sample via chromosomal microarray has been created to help practitioners involved in this process. Conclusion: We recommend that CNV’s involving autosomal recessive genes identified by CMA be treated as any other carrier status. The parents should be encouraged to pursue genetic testing to determine their carrier status of the autosomal recessive conditions and/or additional prenatal diagnostic test on the fetus. [ABSTRACT FROM AUTHOR]

Introduction: Nephronophthisis (NPHP) is a tubulointerstitial kidney disorder with an autosomal recessive inheritance pattern. Its genetic heterogeneity contributes to phenotype variability. The most frequent etiology of juvenile nephronophthisis is a mutation in the nephronophthisis type 1 (NPHP1) gene. This study aimed to evaluate the genotype-phenotype correlation in NPHP1 gene mutation. Methods: A multicenter retrospective study was performed over 20 years from 1998 to 2018 to describe the clinical, biological, and radiological features associated with the large deletion NPHP1 gene in 32 patients. Results: The incidence of NPHP1 was 1.6/204041. Eighty-one percent of our patients were born out of consanguineous marriages. The mean age at diagnosis was 14 ± 7 years. The patients were divided into three groups: isolated nephronophthisis (72%), syndromic nephronophthisis (19%), and patients without recognizable syndrome (9%). Intrafamilial and geographical variability was observed in syndrome diagnoses and in age at the onset of CKD stage 5. Genotype frequency varied between 50% and 100% in genealogical data. Juvenile (47%), adolescent (37%), and adult (13%) clinical forms have been distinguished by the onset of CKD stage 5. The five-year survival rate of renal transplantation was 80%. Conclusion: Given the broad clinical spectrum of NPHP1 associated with the large deletion of the NPHP1 gene, no genotype-phenotype correlation could be established. [ABSTRACT FROM AUTHOR]

Background: Caroli's disease is characterized by non-obstructive dilatation of intrahepatic biliary radicals with formation of calculi followed by recurrent episodes of cholangitis. It is a rare congenital malformation and often remains silent, diagnosed accidentally. But if kept unattended, and without any early intervention, it may lead to fatal residual complications. Hence, its early recognition is of utmost importance to prevent recurrent cholangitis, hepatic abscess, liver cirrhosis and cholangiocarcinoma. Hence, we feel that this case must be reported so as to increase awareness among physicians regarding this entity. Case presentation: We hereby report a case of 10-year-old boy who reported with complaints of recurrent episodes of fever, breathing difficulty and multiple episodes of epigastric abdominal pain with apparently healthy siblings. His routine investigation, laboratory parameters were within normal limits. Ultrasonography abdomen showed liver with normal echo-texture with varying sized multiple thin walled cysts involving both the lobes, right more than left with saccular dilatation of 2nd and 3rd order intra-hepatic biliary radicals without calcification without any colour flow on Doppler evaluation. The common hepatic and common bile ducts were normal in calibre and lumen. Magnetic resonance imaging abdomen had similar findings and upper GI endoscopy was also normal. He was finally diagnosed to be a case of Caroli's disease and was managed with broad spectrum antibiotics, ursodeoxycholic acid, multivitamins, and calcium supplements. He made an uneventful recovery thereafter. Parents were counselled about the risk of cholangitis and cholangiocarcinoma and was referred to tertiary care centre for genetic counselling and for future need of liver transplantation. Conclusion: Age presentation of Caroli's disease varies. Majority present during adolescence and early adulthood. This often poses a diagnostic challenge owing its rare entity and silent presentation. A strong index of suspicion and prompt diagnosis is warranted to prevent its fatal residual complications. [ABSTRACT FROM AUTHOR]

Purpose: Report on the diagnosis of prenatally detected fetal kidneys with bilateral polycystic appearance in a single center between 1999 and 2020 with special focus on renal morphology and biometry, amniotic fluid and extrarenal findings and proposal for an diagnostic algorithm. Methods: Retrospective observational study including pregnancies with prenatally detected kidneys with bilateral polycystic appearance (n = 98). Cases and outcomes were compared according to prenatal findings with special focus on renal morphology, amount of amniotic fluid, and presence of extrarenal abnormalities. Results: Most frequent diagnoses were autosomal recessive polycystic kidney disease (ARPKD, 53.1%), Meckel–Gruber syndrome (MKS, 17.3%) and autosomal dominant polycystic kidney disease (ADPKD, 8.2%). Other diagnoses included: Joubert-, Jeune-, McKusick–Kaufman- and Bardet–Biedl syndrome, overgrowth syndromes, Mainzer–Saldino syndrome and renal tubular dysgenesis. Renal abnormalities most frequently observed were hyperechogenic parenchyma, kidney enlargement, changes of corticomedullary differentiation and cystic changes of various degree. Oligo- and anhydramnios were mainly seen in ARPKD, RTD and second-trimester MKS. Extrarenal findings included skeletal (35.7%) and cardiac (34.7%) abnormalities as well as abnormalities of the central nervous system (27.6%). Conclusion: Gestational age at manifestation, kidney size, visibility of cysts, echogenicity, amniotic fluid volume, and the presence of associated extrarenal malformations allow to differentiate between the most frequent underlying diseases presenting with bilateral polycystic kidneys on prenatal ultrasound by following a diagnostic algorithm. [ABSTRACT FROM AUTHOR]

A rare congenital hepatobiliary disorder called Caroli's disease is characterized by multifocal segmental dilatation of intrahepatic bile ducts that can affect the entire liver or only specific areas of it. Coexisting conditions with Caroli's disease include autosomal dominant polycystic kidney disease (ADPKD) and autosomal recessive polycystic kidney disease (ARPKD). ADPKD results in the development of cysts, which are tiny fluid-filled sacs, in the kidneys. Caroli's disease is considered a rare disorder, affecting a small number of individuals worldwide. The symptoms of Caroli's disease can vary from person to person and it also may overlap with other liver and biliary disorders. As a result, it may be challenging to diagnose and manage the condition due to limited awareness and expertise. Increased awareness, research, and specialized medical care are crucial in improving outcomes for individuals affected by this rare disorder. This study involves the case of a 60- year-old woman presented with abdominal pain, fever, weight loss, and jaundice. Her imaging test endoscopic retrograde cholangiopancreatography (ERCP) signifies Caroli's disease with pancreatic duct (PD) calculi and management involves supportive care with antibiotics. Antibiotics were prescribed to prevent or treat infections such as cholangitis and nutritional supplement was recommended in managing Caroli's disease. The patient underwent pancreatic stent placement and was discharged with regular follow-up. So, this case highlights the clinical and diagnostic aspects to improve disease understanding and the progression of Caroli's illness along with ADPKD. [ABSTRACT FROM AUTHOR]

Autosomal-recessive polycystic kidney disease (ARPKD; MIM #263200) is a severe, hereditary, hepato-renal fibrocystic disorder that causes early childhood morbidity and mortality. Mutations in the polycystic kidney and hepatic disease 1 (PKHD1) gene, which encodes the protein fibrocystin/polyductin complex (FPC), cause all typical forms of ARPKD. Several mouse lines carrying diverse, genetically engineered disruptions in the orthologous Pkhd1 gene have been generated, but none expresses the classic ARPKD renal phenotype. In the current study, we characterized a spontaneous mouse Pkhd1 mutation that is transmitted as a recessive trait and causes cysticliver (cyli), similar to the hepato-biliary disease in ARPKD, but which is exacerbated by age, sex, and parity. We mapped the mutation to Chromosome 1 and determined that an insertion/deletion mutation causes a frameshift within Pkhd1 exon 48, which is predicted to result in a premature termination codon (UGA). Pkhd1cyli/cyli (cyli) mice exhibit a severe liver pathology but lack renal disease. Further analysis revealed that several alternatively spliced Pkhd1 mRNA, all containing exon 48, were expressed in cyli kidneys, but in lower abundance than in wild-type kidneys, suggesting that these transcripts escaped from nonsense-mediated decay (NMD). We identified an AAAAAT motif in exon 48 upstream of the cyli mutation which could enable ribosomal frameshifting, thus potentially allowing production of sufficient amounts of FPC for renoprotection. This mechanism, expressed in a species-specific fashion, may help explain the disparities in the renal phenotype observed between Pkhd1 mutant mice and patients with PKHD1-related disease. Key messages: The Pkhd1cyli/cyli mouse expresses cystic liver disease, but no kidney phenotype. Pkhd1 mRNA expression is decreased in cyli liver and kidneys compared to wild-type. Ribosomal frameshifting may be responsible for Pkhd1 mRNA escape from NMD. Pkhd1 mRNA escape from NMD could contribute to the absent kidney phenotype. [ABSTRACT FROM AUTHOR]

Metformin (MET) has the potential to activate p‐AMPK and block mTORC1‐induced proliferation of tubular cells in PKD kidneys. The aim of this study was to determine the effects of MET on cyst growth, kidney function, AMPK and mTOR signaling, and lactate levels in male PCK rats, a Pkhd1 gene mutation model of human autosomal recessive polycystic kidney disease (ARPKD). MET 300 mg/kg/day IP from days 28 to 84 of age resulted in a mean serum metformin level that was 10 times the upper limit of therapeutic, no effect on cyst indices, nephrotoxicity, and increased serum lactate. MET 150 mg/kg resulted in a therapeutic serum metformin level but had no effect on kidney weight, cyst indices, kidney function, or mTOR and autophagy proteins. In summary, a standard dose of MET was ineffective in reducing PKD, did not activate p‐AMPK or suppress mTOR and the higher dose resulted in increased lactate levels and nephrotoxicity. In conclusion, the study dampens enthusiasm for human studies of MET in PKD. Doubling the metformin dose resulted in a 10‐fold increase in mean blood levels and toxicity suggesting that the dosage range between therapeutic and toxic is narrow. [ABSTRACT FROM AUTHOR]

Objective: Variants of the polycystic kidney and hepatic disease 1 (PKHD1) gene are associated with autosomal recessive polycystic kidney disease (ARPKD). This study aimed to identify the genetic causes in a Chinese pedigree with ARPKD and design a minigene construct of the PKHD1 gene to investigate the impact of its variants on splicing. Methods: Umbilical cord samples from the proband and peripheral blood samples from his parents were collected, and genomic DNA was extracted for wholeexome sequencing (WES). Bioinformatic analysis was used to identify potential genetic causes, and Sanger sequencing confirmed the existence of variants within the pedigree. A minigene assay was performed to validate the effects of an intronic variant on mRNA splicing. Results: Two variants, c.9455del (p.N3152Tfs*10) and c.2408-13C>G, were identified in the PKHD1 gene (NM_138694.4) by WES; the latter has not been previously reported. In silico analysis predicted that this intronic variant is potentially pathogenic. Bioinformatic splice prediction tools revealed that the variant is likely to strongly impact splice site function. An in vitro minigene assay revealed that c.2408-13C>G can cause aberrant splicing, resulting in the retention of 12 bp of intron 23. Conclusion: A novel pathogenic variant of PKHD1, c.2408-13C>G, was found in a fetus with ARPKD, which enriches the variant spectrum of the PKHD1 gene and provides a basis for genetic counseling and the diagnosis of ARPKD. Minigenes are optimal to determine whether intron variants can cause aberrant splicing. [ABSTRACT FROM AUTHOR]

Objectives: To compile a list of instant diagnoses of major fetal anomalies, and to present their sonographic descriptors and test them in a retrospective series of fetuses with congenital anomalies managed at our center. Methods: The first step was to identify major anomalies that meet the following criteria: (1) can be diagnosed directly and unequivocally on the basis of a set of descriptors evident on a single sonographic view; (2) are among those more commonly diagnosed in utero; (3) represent major lethal or life‐threatening malformations or anomalies for which no or only palliative surgery can be performed. For each of these anomalies, a sonographic descriptor was produced. The second step was to test the descriptors of the instant diagnoses in all cases with these anomalies evaluated since January 2000 in our Fetal Medicine Unit, retrieved from our electronic database. For each congenital anomaly–sonographic descriptor pair we then evaluated the presence vs absence of an unequivocal relationship between anomaly and descriptor, assessing: whether a particular descriptor in a set reference plane identified unequivocally the anomaly, i.e. the same descriptor could not be found in any other malformation; and whether a particular anomaly presented the corresponding descriptor in all cases. Finally, we evaluated whether the sonographic descriptors could be applied in all trimesters or only selectively, considering the natural history of the 20 instant diagnoses. Results: Of the 20 instant diagnoses, five involved the central/peripheral nervous system (exencephaly/anencephaly, alobar/semilobar holoprosencephaly, cephalocele, open spinal dysraphism, complete agenesis of corpus callosum), five involved the heart (hypoplastic left heart syndrome, complete atrioventricular septal defect, severe Ebstein's anomaly, critical aortic stenosis, transposition of the great arteries), five involved the abdominal wall (left‐sided congenital diaphragmatic hernia, exomphalos, gastroschisis, body‐stalk anomaly) or gastrointestinal tract (duodenal atresia), and five involved the remaining systems (three urinary (autosomal recessive polycystic kidney disease, multicystic dysplastic kidney, lower urinary tract obstruction), two skeletal (transverse limb defect, radial ray defect)). All of the descriptors were found to identify unequivocally the related malformations, whereas four of the malformations were not associated with their reference descriptors in every case. For example, congenital diaphragmatic hernia (left‐sided) presented without the stomach in the thorax in 42/93 (45.2%) cases. Due to the natural history of the condition, not all signs were recognizable in the first trimester, some becoming evident only from the second trimester onwards. Conclusion: We have defined sonographic descriptors that enable an unequivocal instant diagnosis for a list of 20 major congenital anomalies: the 'INDIAMAN‐20' (INstant DIAgnosis of Major ANomalies) protocol. We believe that using this approach may facilitate focused training of less experienced operators and that it may be incorporated into artificial intelligence and deep learning protocols, further boosting the instant prenatal recognition of these lethal or life‐threatening malformations. © 2022 International Society of Ultrasound in Obstetrics and Gynecology. [ABSTRACT FROM AUTHOR]

Systemic and portal hypertension, liver fibrosis, and hepatomegaly are manifestations associated with autosomal recessive polycystic kidney disease (ARPKD), which is caused by malfunctions of fibrocystin/polyductin (FPC). The goal is to understand how liver pathology occurs and to devise therapeutic strategies to treat it. We injected 5-day-old Pkhd1del3-4/del3-4 mice for 1 mo with the cystic fibrosis transmembrane conductance regulator (CFTR) modulator VX-809 designed to rescue processing and trafficking of CFTR folding mutants. We used immunostaining and immunofluorescence techniques to evaluate liver pathology. We assessed protein expression via Western blotting. We detected abnormal biliary ducts consistent with ductal plate abnormalities, as well as a greatly increased proliferation of cholangiocytes in the Pkhd1del3-4/del3-4 mice. CFTR was present in the apical membrane of cholangiocytes and increased in the Pkhd1del3-4/del3-4 mice, consistent with a role for apically located CFTR in enlarged bile ducts. Interestingly, we also found CFTR in the primary cilium, in association with polycystin (PC2). Localization of CFTR and PC2 and overall length of the cilia were increased in the Pkhd1del3-4/del3-4 mice. In addition, several of the heat shock proteins; 27, 70, and 90 were upregulated, suggesting that global changes in protein processing and trafficking had occurred. We found that a deficit of FPC leads to bile duct abnormalities, enhanced cholangiocyte proliferation, and misregulation of heat shock proteins, which all returned toward wild type (WT) values following VX-809 treatment. These data suggest that CFTR correctors can be useful as therapeutics for ARPKD. Given that these drugs are already approved for use in humans, they can be fast-tracked for clinical use. NEW & NOTEWORTHY ARPKD is a multiorgan genetic disorder resulting in newborn morbidity and mortality. There is a critical need for new therapies to treat this disease. We show that persistent cholangiocytes proliferation occurs in a mouse model of ARPKD along with mislocalized CFTR and misregulated heat shock proteins. We found that VX-809, a CFTR modulator, inhibits proliferation and limits bile duct malformation. The data provide a therapeutic pathway for strategies to treat ADPKD. [ABSTRACT FROM AUTHOR]

Phosphomannomutase 2 (PMM2) deficiency causes Congenital Disorder of Glycosylation (PMM2-CDG), but does not have a recognised association with Inflammatory Bowel Disease (IBD). A distinct clinical syndrome of hyperinsulinism and autosomal recessive polycystic kidney disease (HIPKD) arises in the context of a specific variant in the PMM2 promotor, either in homozygosity, or compound heterozygous with a deleterious PMM2 variant. Here, we describe the development of IBD in three patients with PMM2-HIPKD, with onset of IBD at 0, 6, and 10 years of age. In each case, intestinal inflammation coincided with the unusual finding of gastric antral foveolar hyperplasia. IBD disease was of variable severity at onset but well controlled with conventional and first-line biologic treatment approaches. The organ-level pattern of disease manifestations in PMM2-HIPKD-IBD may reflect a loss of cis-acting regulatory control by hepatocyte nuclear factor 4 alpha (HNF4A). Analysis of published transcriptomic data suggests that IBD most likely arises due to an impact on epithelial cellular function. We identify a specific pattern of variation in PMM2 as a novel association of early-onset IBD with distinctive gastric pathology. [ABSTRACT FROM AUTHOR]

Background: Autosomal recessive polycystic kidney disease (ARPKD) is a significant cause of morbidity and mortality in infants and children. In severe cases bilateral nephrectomies are considered but may be associated with significant neurological complications and life-threatening hypotension. Case presentation: We describe a case of a 17 months old boy with genetically confirmed ARPKD who underwent sequential bilateral nephrectomies at the age of 4 and 10 months. Following the second nephrectomy the boy was started on continuous cycling peritoneal dialysis with blood pressure on the lower range. At the age of 12 months after a few days of poor feeding at home the boy experienced a severe episode of hypotension and coma of Glasgow Come Scale of three. Brain magnetic-resonance imaging (MRI) showed signs of hemorrhage, cytotoxic cerebral edema and diffuse cerebral atrophy. During the subsequent 72 h he developed seizures requiring anti-epileptic drug therapy, gradually regained consciousness but remained significantly hypotensive after discontinuation of vasopressors. Thus, he received high doses of sodium chloride orally and intraperitoneally as well as midodrine hydrochloride. His ultrafiltration (UF) was targeted to keep him in mild-to-moderate fluid overload. After two months of stable condition the patient started to develop hypertension requiring four antihypertensive medications. After optimizing peritoneal dialysis to avoid fluid overload and discontinuation of sodium chloride the antihypertensives were discontinued, but hyponatremia with hypotensive episodes reoccurred. Sodium chloride was reintroduced resulting in recurrent salt-dependent hypertension. Conclusions: Our case report illustrates an unusual course of blood pressure changes following bilateral nephrectomies in an infant with ARPKD and the particular importance of tight regulation of sodium chloride supplementation. The case adds to the scarce literature about clinical sequences of bilateral nephrectomies in infants, and as well highlights the challenge of managing blood pressure in these patients. Further research on the mechanisms and management of blood pressure control is clearly needed. [ABSTRACT FROM AUTHOR]

Measurement of total kidney volume (TKV) using magnetic resonance imaging (MRI) is a valuable approach for monitoring disease progression in autosomal dominant polycystic kidney disease (PKD) and is becoming more common in preclinical studies using animal models. Manual contouring of kidney MRI areas [i.e., manual method (MM)] is a conventional, but time-consuming, way to determine TKV. We developed a template-based semiautomatic image segmentation method (SAM) and validated it in three commonly used PKD models: Cys1cpk/cpk mice, Pkd1RC/RC mice, and Pkhd1pck/pck rats (n = 10 per model). We compared SAM-based TKV with that obtained by clinical alternatives including the ellipsoid formula-based method (EM) using three kidney dimensions, the longest kidney length method (LM), and MM, which is considered the gold standard. Both SAM and EM presented high accuracy in TKV assessment in Cys1cpk/cpk mice [interclass correlation coefficient (ICC) ≥ 0.94]. SAM was superior to EM and LM in Pkd1RC/RC mice (ICC = 0.87, 0.74, and <0.10 for SAM, EM, and LM, respectively) and Pkhd1pck/pck rats (ICC = 0.59, <0.10, and <0.10, respectively). Also, SAM outperformed EM in processing time in Cys1cpk/cpk mice (3.6 ± 0.6 vs. 4.4 ± 0.7 min/kidney) and Pkd1RC/RC mice (3.1 ± 0.4 vs. 7.1 ± 2.6 min/kidney, both P < 0.001) but not in Pkhd1PCK/PCK rats (3.7 ± 0.8 vs. 3.2 ± 0.5 min/kidney). LM was the fastest ~1 min) but correlated most poorly with MM-based TKV in all studied models. Processing times by MM were longer for Cys1cpk/cpk mice, Pkd1RC/RC mice, and Pkhd1pck.pck rats (66.1 ± 7.3, 38.3 ± 7.5, and 29.2 ± 3.5 min). In summary, SAM is a fast and accurate method to determine TKV in mouse and rat PKD models. [ABSTRACT FROM AUTHOR]

ARPKD is a rare, infantile form of PCKD. It's a Ciliopathic disorder with multi-organ involvement. The pathognomonic features are predominately seen in the kidneys and liver. We herein report a case of ARPKD that presented in an antenatal mother whose prenatal screening ultrasonogram revealed enlarged, echogenic kidney with severe oligohydramnios. ARPKD was suspected and due to its poor compatibility with life, patient underwent MTP. Fetal autopsy confirmed ARPKD with potter's sequence - oligohydramnios and CTEV. This extremely rare ARPKD associated with CTEV was seen in only one other published case in India. [ABSTRACT FROM AUTHOR]

This article, published in the journal Ultrasound in Obstetrics & Gynecology, discusses two cases of prenatal diagnosis of Bardet-Biedl Syndrome (BBS), a rare genetic disorder. The main finding in both cases was large, echogenic kidneys on prenatal imaging. BBS is characterized by renal dystrophy and malformations, polydactyly, intellectual disability, central obesity, and hypogonadism. Genetic testing confirmed BBS in both cases, with different mutated copies of the BBS10 and BBS1 genes. The article provides valuable information for researchers and healthcare professionals studying genetic abnormalities and prenatal diagnoses. [Extracted from the article]

Mechanosensitive TRPV4 channel plays a dominant role in maintaining [Ca2+]i homeostasis and flow‐sensitive [Ca2+]i signaling in the renal tubule. Polycystic kidney disease (PKD) manifests as progressive cyst growth due to cAMP‐dependent fluid secretion along with deficient mechanosensitivity and impaired TRPV4 activity. Here, we tested how regulation of renal TRPV4 function by dietary K+ intake modulates the rate of cystogenesis and mechanosensitive [Ca2+]i signaling in cystic cells of PCK453 rats, a homologous model of human autosomal recessive PKD (ARPKD). One month treatment with both high KCl (5% K+) and KB/C (5% K+ with bicarbonate/citrate) diets significantly increased TRPV4 levels when compared to control (0.9% K+). High KCl diet caused an increased TRPV4‐dependent Ca2+ influx, and partial restoration of mechanosensitivity in freshly isolated monolayers of cystic cells. Unexpectedly, high KB/C diet induced an opposite effect by reducing TRPV4 activity and worsening [Ca2+]i homeostasis. Importantly, high KCl diet decreased cAMP, whereas high KB/C diet further increased cAMP levels in cystic cells (assessed as AQP2 distribution). At the systemic level, high KCl diet fed PCK453 rats had significantly lower kidney‐to‐bodyweight ratio and reduced cystic area. These beneficial effects were negated by a concomitant administration of an orally active TRPV4 antagonist, GSK2193874, resulting in greater kidney weight, accelerated cystogenesis, and augmented renal injury. High KB/C diet also exacerbated renal manifestations of ARPKD, consistent with deficient TRPV4 activity in cystic cells. Overall, we demonstrate that TRPV4 channel activity negatively regulates cAMP levels in cystic cells thus attenuating (high activity) or accelerating (low activity) ARPKD progression. [ABSTRACT FROM AUTHOR]

Exploration into the causes of hereditary renal cystic diseases demonstrates a deep-rooted connection with the proteomic components of the cellular organelle cilia. Cilia are essential to the signaling cascades, and their dysfunction has been tied to a range of renal cystic diseases initiating with studies on the oak ridge polycystic kidney (ORPK) mouse model. Here, we delve into renal cystic pathologies that have been tied with ciliary proteosome and highlight the genetics associated with each. The pathologies are grouped based on the mode of inheritance, where inherited causes that result in cystic kidney disease phenotypes include autosomal dominant and autosomal recessive polycystic kidney disease, nephronophthisis (Bardet--Biedl syndrome and Joubert Syndrome), and autosomal dominant tubulointerstitial kidney disease. Alternatively, phakomatoses-, also known as neurocutaneous syndromes, associated cystic kidney diseases include tuberous sclerosis (TS) and Von Hippel--Lindau (VHL) disease. Additionally, we group the pathologies by the mode of inheritance to discuss variations in recommendations for genetic testing for biological relatives of a diagnosed individual. [ABSTRACT FROM AUTHOR]

(1) Background: Autosomal recessive polycystic kidney disease (ARPKD) is a rare ciliopathy characterized by progressively enlarged kidneys with fusiform dilatation of the collecting ducts. Loss-of-function mutations in the PKHD1 gene, which encodes fibrocystin/polyductin, cause ARPKD; however, an efficient treatment method and drug for ARPKD have yet to be found. Antisense oligonucleotides (ASOs) are short special oligonucleotides which function to regulate gene expression and alter mRNA splicing. Several ASOs have been approved by the FDA for the treatment of genetic disorders, and many are progressing at present. We designed ASOs to verify whether ASOs mediate the correction of splicing further to treat ARPKD arising from splicing defects and explored them as a potential treatment option. (2) Methods: We screened 38 children with polycystic kidney disease for gene detection using whole-exome sequencing (WES) and targeted next-generation sequencing. Their clinical information was investigated and followed up. The PKHD1 variants were summarized and analyzed, and association analysis was carried out to analyze the relationship between genotype and phenotype. Various bioinformatics tools were used to predict pathogenicity. Hybrid minigene analysis was performed as part of the functional splicing analysis. Moreover, the de novo protein synthesis inhibitor cycloheximide was selected to verify the degraded pathway of abnormal pre-mRNAs. ASOs were designed to rescue aberrant splicing, and this was verified. (3) Results: Of the 11 patients with PKHD1 variants, all of them exhibited variable levels of complications of the liver and kidneys. We found that patients with truncating variants and variants in certain regions had a more severe phenotype. Two splicing variants of the PKHD1 genotypes were studied via the hybrid minigene assay: variants c.2141-3T>C and c.11174+5G>A. These cause aberrant splicing, and their strong pathogenicity was confirmed. We demonstrated that the abnormal pre-mRNAs produced from the variants escaped from the NMD pathway with the use of the de novo protein synthesis inhibitor cycloheximide. Moreover, we found that the splicing defects were rescued by using ASOs, which efficiently induced the exclusion of pseudoexons. (4) Conclusion: Patients with truncating variants and variants in certain regions had a more severe phenotype. ASOs are a potential drug for treating ARPKD patients harboring splicing mutations of the PKHD1 gene by correcting the splicing defects and increasing the expression of the normal PKHD1 gene. [ABSTRACT FROM AUTHOR]

Purpose: Autosomal recessive polycystic kidney disease (ARPKD) is a hereditary condition characterized by massive kidney enlargement and developmental liver defects. Potential consequences during childhood include the need for kidney replacement therapy (KRT). We report the design of 2 ongoing clinical trials (Study 204, Study 307) to evaluate safety, tolerability, and efficacy of tolvaptan in children with ARPKD. Methods: Both trials are of multinational, multicenter, open-label design. Age range at enrollment is 28 days to < 12 weeks in Study 204 and 28 days to < 18 years in Study 307. Subjects in both studies must have a clinical diagnosis of ARPKD, and those in Study 204 must additionally have signs indicative of risk of rapid progression to KRT, namely, all of: nephromegaly, multiple kidney cysts or increased kidney echogenicity suggesting microcysts, and oligohydramnios or anhydramnios. Target enrollment is 20 subjects for Study 204 and ≥ 10 subjects for Study 307. Results: Follow-up is 24 months in Study 204 (with optional additional treatment up to 36 months) and 18 months in Study 307. Outcomes include safety, tolerability, change in kidney function, and percentage of subjects requiring KRT relative to historical data. Regular safety assessments monitor for possible adverse effects of treatment on parameters such as liver function, kidney function, fluid balance, electrolyte levels, and growth trajectory, with increased frequency of monitoring following tolvaptan initiation or dose escalation. Conclusions: These trials will provide data on tolvaptan safety and efficacy in a population without disease-specific treatment options. Trial registration: Study 204: EudraCT 2020–005991-36; Study 307: EudraCT 2020–005992-10. [ABSTRACT FROM AUTHOR]

We present a fetus with bilaterally enlarged and echogenic kidneys. Prenatal testing detected compound heterozygosity for a 0.676 Mb de novo deletion and an inherited pathogenic variant in PKHD1. This is the first case of autosomal recessive polycystic kidney disease (ARPKD) with a prenatally detected disease‐causing PKHD1 deletion. [ABSTRACT FROM AUTHOR]

Objective: Rare disease Background: The polycystic kidney and hepatic disease 1 (PKHD1) gene codes for fibrocystin-polyductin, a protein that takes part in cell-signaling for cell differentiation, especially in kidney tubules and bile ducts. A homozygous or compound heterozygous defect in this gene can cause autosomal recessive polycystic kidney disease (ARPKD). Polycystic liver disease (PCLD) can also be caused by single heterozygous variants in the PKHD1 gene. ARPKD presents with renal insufficiency and cystic dilatation of bile ducts, although disease is not expected with a single heterozygous mutation. PCLD presents with multiple cysts in the liver and dilated bile ducts as well, but with less of an impact on the kidneys than with ARPKD. Our purpose in publishing this report is to introduce an as-yet unknown variant to the body of genetic defects associated with ARPKD and PCLD, as well as to argue for the likely pathogenicity of the variant according to the prevailing criteria used for classifying gene variants. Case Report: We present a patient with a de novo PKHD1 variant currently classified as a variant of unknown significance manifesting with bilaterally enlarged cystic kidneys and echogenic cystic structures in the hepatic portal system, indicative of cystic disease. Conclusions: Given this patient's liver and kidney presentation that does not fully align with either ARPKD or PCLD, the au- thors believe that the single heterozygous variant in this patient's PKHD1 gene is worthy of reporting. This new single heterozygous variant in PKHD1 gene causing cystic kidney and cystic hepatic disease in the patient should be considered 'likely pathogenic' according to the criteria set by the American College of Medical Genetics. [ABSTRACT FROM AUTHOR]

Autosomal dominant polycystic kidney disease, autosomal recessive polycystic kidney disease, and nephronophthisis are hereditary disorders with the occurrence of numerous cysts in both kidneys, often causing chronic and end-stage renal failure. Animal models have played an important role in recent advances in research not only on disease onset and progressive mechanisms but also on the development of therapeutic interventions. For a long time, spontaneous animal models have been used as the primary focus for human diseases; however, after the identification of the nucleotide sequence of the responsible genes, PKD1, PKD2, PKHD1, and NPHPs, various types of genetically modified models were developed by genetic and reproductive engineering techniques and played the leading role in the research field. In this review, we present murine models of hereditary renal cystic diseases, discussing their potential benefits in the development of therapeutic strategies. [ABSTRACT FROM AUTHOR]

Introduction: Kindler syndrome is an autosomal recessive disorder with multisystem involvement such as cutaneous, oral, gastrointestinal, and urogenital manifestations. Rationale: Timely diagnosis and management of this syndrome are warranted. The dental surgeon has a prime role in diagnosing the same and halting the progression of gingivitis to periodontitis and referring the patient to appropriate specialists for effective and timely management of the same. Patient Concerns: In this case report, a 17-year-old patient had reported with the chief complaint of spontaneous bleeding from gums and swollen gums since birth, and blackish pigmentation of the skin. Diagnosis: On examination, the patient had poikiloderma, photosensitivity, gingival fragility, and skin atrophy suggesting a diagnosis of Kindler syndrome. Interventions: Oral prophylaxis was done for the patient on several sittings and the patient was on continuous follow-up for 2 years. Dermatology and urology opinions were sought and advice was followed. Outcomes: The patient had complete regression of spontaneous gingival bleeding and oral hygiene had also become satisfactory. Lesson: Prompt diagnosis of the disease with appropriate and early intervention by a dental surgeon could definitely stop the disease progression. [ABSTRACT FROM AUTHOR]

Autosomal Recessive Polycystic Kidney Disease (ARPKD) is a rare paediatric disease primarily caused by sequence variants in PKHD1. ARPKD presents with considerable clinical variability relating to the type of PKHD1 sequence variant, but not its position. Animal models of Polycystic Kidney Disease (PKD) suggest a complex genetic landscape, with genetic modifiers as a potential cause of disease variability. To investigate in an unbiased manner the molecular mechanisms of ARPKD and identify potential indicators of disease severity, Whole Exome Sequencing (WES) and RNA-Sequencing (RNA-Seq) were employed on human ARPKD kidneys and age-matched healthy controls. WES confirmed the clinical diagnosis of ARPKD in our patient cohort consisting of ten ARPKD kidneys. Sequence variant type, nor position of PKHD1 sequence variants, was linked to disease severity. Sequence variants in genes associated with other ciliopathies were detected in the ARPKD cohort, but only PKD1 could be linked to disease severity. Transcriptomic analysis on a subset of four ARPKD kidneys representing severe and moderate ARPKD, identified a significant number of genes relating to WNT signalling, cellular metabolism and development. Increased expression of WNT signalling-related genes was validated by RT-qPCR in severe and moderate ARPKD kidneys. Two individuals in our cohort with the same PKHD1 sequence variants but different rates of kidney disease progression, with displayed transcriptomic differences in the expression of WNT signalling genes. ARPKD kidney transcriptomics highlights changes in WNT signalling as potentially significant in ARPKD manifestation and severity, providing indicators for slowing down the progression of ARPKD. [Display omitted] • Autosomal Recessive Polycystic Kidney Disease (ARPKD) is a rare genetic kidney disease caused by PKHD1 mutations. • WES and RNA-Seq on ARPKD kidneys revealed no link between PKHD1 mutations and severity. • Mutations in ciliopathy genes discovered; only PKD1 correlated with disease severity. • Transcriptomics highlighted WNT signalling, metabolism and development genes in ARPKD. • Varied disease progression in individuals with identical PKHD1 mutations linked to WNT signalling differences. [ABSTRACT FROM AUTHOR]

Background: Hyperinsulinemic hypoglycemia (HH) is an important cause of persistent hypoglycemia in newborns and infants. Recently, PMM2 (phosphomannomutase 2) mutation has been associated with HH, especially in conjunction with polycystic kidney disease (PKD). PMM2 deficiency is one of the most common causes of congenital disorder of glycosylation (CDG). Renal involvement in PMM2-CDG manifests as cystic kidney disease, echogenic kidneys, nephrotic syndrome or mild proteinuria. Case Summary: Here, we describe a pair of siblings with HH associated with autosomal recessive polycystic kidney disease (ARPKD) and PMM2 mutation. Two siblings with ARPKD presented during infancy and early toddler years with severe hypoglycemia. Both had inappropriately elevated serum insulin, low β-hydroxybutyrate, a need for a high glucose infusion rate, positive glycemic response to glucagon, positive diazoxide response and PMM2 mutation. Conclusions: Although this combination of HH and PKD was recently described in patients of European descent who also had PMM2 mutation, our report is unique given that these non-consanguineous siblings were not exclusively of European descent. PMM2 mutation leading to abnormal glycosylation and causing cystic kidneys and the alteration of insulin secretion is the most likely pathogenesis of this clinical spectrum. [ABSTRACT FROM AUTHOR]

Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary cystic kidney disease, with patients often having a positive family history that is characterized by a similar phenotype. However, in atypical cases, particularly those in which family history is unclear, a differential diagnosis between ADPKD and other cystic kidney diseases is important. When diagnosing ADPKD, cystic kidney diseases that can easily be excluded using clinical information include: multiple simple renal cysts, acquired cystic kidney disease (ACKD), multilocular renal cyst/multilocular cystic nephroma/polycystic nephroma, multicystic kidney/multicystic dysplastic kidney (MCDK), and unilateral renal cystic disease (URCD). However, there are other cystic kidney diseases that usually require genetic testing, or another means of supplementing clinical information to enable a differential diagnosis of ADPKD. These include autosomal recessive polycystic kidney disease (ARPKD), autosomal dominant tubulointerstitial kidney disease (ADTKD), nephronophthisis (NPH), oral-facial-digital (OFD) syndrome type 1, and neoplastic cystic kidney disease, such as tuberous sclerosis (TSC) and Von Hippel-Lindau (VHL) syndrome. To help physicians evaluate cystic kidney diseases, this article provides a review of cystic kidney diseases for which a differential diagnosis is required for ADPKD. [ABSTRACT FROM AUTHOR]

Autosomal recessive polycystic kidney disease (ARPKD) is an inherited pathology caused mainly by mutations of the polycystic kidney and hepatic disease 1 (PKHD1) gene, which usually leads to end‐stage renal disease. Previous studies suggested that the P2X purinoreceptor 4 (P2X4R) may play an important role in the progression of ARPKD. To test this hypothesis, we assessed the chronic effects of ivermectin (P2X4R allosteric modulator) and 5‐BDBD (P2X4R antagonist) on the development of ARPKD in PCK/CrljCrl‐Pkhd1pck/CRL (PCK) rats. Our data indicated that activation of ATP‐mediated P2X4R signaling with ivermectin for 6 weeks in high dose (50 mg/L; water supplementation) decreased the total body weight of PCK rats while the heart and kidney weight remained unaffected. Smaller doses of ivermectin (0.5 or 5 mg/L, 6 weeks) or the inhibition of P2X4R signaling with 5‐BDBD (18 mg/kg/day, food supplement for 8 weeks) showed no effect on electrolyte balance or the basic physiological parameters. Furthermore, cystic index analysis for kidneys and liver revealed no effect of smaller doses of ivermectin (0.5 or 5 mg/L) and 5‐BDBD on the cyst development of PCK rats. We observed a slight increase in the cystic liver index on high ivermectin dose, possibly due to the cytotoxicity of the drug. In conclusion, this study revealed that pharmacological modulation of P2X4R by ivermectin or 5‐BDBD does not affect the development of ARPKD in PCK rats, which may provide insights for future studies on investigating the therapeutic potential of adenosine triphosphate (ATP)‐P2 signaling in PKD diseases. [ABSTRACT FROM AUTHOR]