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The ordinarily benign activity of basaltic volcanoes is periodically interrupted by violent paroxysmal explosions ranging in size from Hawaiian to Plinian in the most extreme examples. These paroxysms often occur suddenly and with limited or no precursors, leaving their causal mechanisms still incompletely understood. Two such events took place in summer 2019 at Stromboli, a volcano otherwise known for its persistent mild open-vent activity, resulting in one fatality and damage to infrastructure. Here, we use a post hoc analysis and reinterpretation of volcanic gas compositions and fluxes acquired at Stromboli to show that the two paroxysms were preceded by detectable escalations in volcanic plume CO 2 degassing weeks to months beforehand. Our results demonstrate that volcanic gas CO 2 is a key driver of explosions and that the preparatory periods ahead of explosions in basaltic systems can be captured by precursory CO 2 leakage from deeply stored mafic magma.

The mild activity of basaltic volcanoes is punctuated by violent explosive eruptions that occur without obvious precursors. Modelling the source processes of these sudden blasts is challenging. Here, we use two decades of ground deformation (tilt) records from Stromboli volcano to shed light, with unprecedented detail, on the short-term (minute-scale) conduit processes that drive such violent volcanic eruptions. We find that explosive eruptions, with source parameters spanning seven orders of magnitude, all share a common pre-blast ground inflation trend. We explain this exponential inflation using a model in which pressure build-up is caused by the rapid expansion of volatile-rich magma rising from depth into a shallow (<400 m) resident magma conduit. We show that the duration and amplitude of this inflation trend scales with the eruption magnitude, indicating that the explosive dynamics obey the same (scale-invariant) conduit process. This scale-invariance of pre-explosion ground deformation may usher in a new era of short-term eruption forecasting.

We provide data on fetal growth pattern on the molecular subtypes of Beckwith-Wiedemann syndrome (BWS): IC1 gain of methylation (IC1-GoM), IC2 loss of methylation (IC2-LoM), 11p15.5 paternal uniparental disomy (UPD), and CDKN1C mutation. In this observational study, gestational ages and neonatal growth parameters of 247 BWS patients were compared by calculating gestational age-corrected standard deviation scores (SDS) and proportionality indexes to search for differences among IC1-GoM (n = 21), UPD (n = 87), IC2-LoM (n = 147), and CDKN1C mutation (n = 11) patients. In IC1-GoM subgroup, weight and length are higher than in other subgroups. Body proportionality indexes display the following pattern: highest in IC1-GoM patients, lowest in IC2-LoM/CDKN1C patients, intermediate in UPD ones. Prematurity was significantly more prevalent in the CDKN1C (64%) and IC2-LoM subgroups (37%). Fetal growth patterns are different in the four molecular subtypes of BWS and remarkably consistent with altered gene expression primed by the respective molecular mechanisms. IC1-GoM cases show extreme macrosomia and severe disproportion between weight and length excess. In IC2-LoM/CDKN1C patients, macrosomia is less common and associated with more proportionate weight/length ratios with excess of preterm birth. UPD patients show growth patterns closer to those of IC2-LoM, but manifest a body mass disproportion rather similar to that seen in IC1-GoM cases., (© 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Rubinstein-Taybi syndrome (RSTS) is a rare, clinically heterogeneous disorder characterized by cognitive impairment and several multiple congenital anomalies. The syndrome is caused by almost private point mutations in the CREBBP (~55% of cases) and EP300 (~8%) genes. The CREBBP mutational spectrum is variegated and characterized by point mutations (30-50 %) and deletions (~10%). The latter are diverse in size and genomic position and remove either the whole CREBBP gene and its flanking regions or only an intragenic portion. Here, we report 14 novel CREBBP deletions ranging from single exons to the whole gene and flanking regions which were identified by applying complementary cytomolecular techniques: fluorescence in situ hybridization, multiplex ligation-dependent probe amplification and array comparative genome hybridization, to a large cohort of RSTS patients. Deletions involving CREBBP account for 23% of our detected CREBBP mutations, making an important contribution to the mutational spectrum. Genotype-phenotype correlations revealed that patients with CREBBP deletions extending beyond this gene did not always have a more severe phenotype than patients harboring CREBBP point mutations, suggesting that neighboring genes play only a limited role in the etiopathogenesis of CREBBP-centerd contiguous gene syndrome. Accordingly, the extent of the deletion is not predictive of the severity of the clinical phenotype.

Background: Beckwith-Wiedemann syndrome (BWS) and hemihyperplasia (HH) are overgrowth conditions with predisposition to hepatoblastoma for which early diagnosis patients undergo cancer screening based on determination of the tumor marker α-fetoprotein (αFP). Repeated blood draws are a burden for patients with consequent compliance issues and poor adherence to surveillance protocol. We sought to analyze feasibility and reliability of αFP dosage using an analytical micromethod based on blood dried on filter paper (DBS)., Methods: Overall 143 coupled αFP determinations on plasma and DBS collected simultaneously were performed, of which 31 were in patients with hepatoblastoma predisposition syndromes and 112 were in controls. The plasma αFP dosage method was adapted to DBS adsorbed on paper matrix for newborn screening., Results: There was strong correlation between plasmatic and DBS αFP (r2 = 0.999, P < 0.001). Cohen's k coefficient for correlation was 0.96 for diagnostic cut-off of 10 U/ml (P < 0.001), commonly employed in clinical practice. The measurements on plasma and DBS were highly overlapping and consistent., Conclusion: The DBS method allowed to dose αFP reliably and consistently for the concentrations commonly employed in clinical settings for the screening of hepatoblastoma, opening new scenarios about conducting cancer screening in overgrowth syndromes.

Background: Conventional karyotyping (550 bands resolution) is able to identify chromosomal aberrations >5-10 Mb, which represent a known cause of intellectual disability/developmental delay (ID/DD) and/or multiple congenital anomalies (MCA). Array-Comparative Genomic Hybridization (array-CGH) has increased the diagnostic yield of 15-20%., Results: In a cohort of 700 ID/DD cases with or without MCA, including 15 prenatal diagnoses, we identified a subgroup of seven patients with a normal karyotype and a large complex rearrangement detected by array-CGH (at least 6, and up to 18 Mb). FISH analysis could be performed on six cases and showed that rearrangements were translocation derivatives, indistinguishable from a normal karyotype as they involved a similar band pattern and size. Five were inherited from a parent with a balanced translocation, whereas two were apparently de novo. Genes spanning the rearrangements could be associated with some phenotypic features in three cases (case 3: DOCK8; case 4: GATA3, AKR1C4; case 6: AS/PWS deletion, CHRNA7), and in two, likely disease genes were present (case 5: NR2F2, TP63, IGF1R; case 7: CDON). Three of our cases were prenatal diagnoses with an apparently normal karyotype., Conclusions: Large complex rearrangements of up to 18 Mb, involving chromosomal regions with similar size and band appearance may be overlooked by conventional karyotyping. Array-CGH allows a precise chromosomal diagnosis and recurrence risk definition, further confirming this analysis as a first tier approach to clarify molecular bases of ID/DD and/or MCA. In prenatal tests, array-CGH is confirmed as an important tool to avoid false negative results due to karyotype intrinsic limit of detection.

Recently, pathogenic variants in the MLL2 gene were identified as the most common cause of Kabuki (Niikawa-Kuroki) syndrome (MIM#147920). To further elucidate the genotype-phenotype correlation, we studied a large cohort of 86 clinically defined patients with Kabuki syndrome (KS) for mutations in MLL2. All patients were assessed using a standardized phenotype list and all were scored using a newly developed clinical score list for KS (MLL2-Kabuki score 0-10). Sequencing of the full coding region and intron-exon boundaries of MLL2 identified a total of 45 likely pathogenic mutations (52%): 31 nonsense, 10 missense and four splice-site mutations, 34 of which were novel. In five additional patients, novel, i.e. non-dbSNP132 variants of clinically unknown relevance, were identified. Patients with likely pathogenic nonsense or missense MLL2 mutations were usually more severely affected (median 'MLL2-Kabuki score' of 6) as compared to the patients without MLL2 mutations (median 'MLL2-Kabuki score' of 5), a significant difference (p < 0.0014). Several typical facial features such as large dysplastic ears, arched eyebrows with sparse lateral third, blue sclerae, a flat nasal tip with a broad nasal root, and a thin upper and a full lower lip were observed more often in mutation positive patients., (© 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Although Beckwith-Wiedemann syndrome (BWS, OMIM #130650) is the most common genetic overgrowth disorder, data on its epidemiology are scanty and the estimates of its occurrence show wide variability. The aim of this study is to assess its prevalence in Piedmont Region (Italy). We included in the study all patients diagnosed with BWS born in Piedmont from 1997 to 2009 through a search in the Italian Registry for Rare Diseases. This source was further validated with data from the network of Regional Clinical Genetics services and surveys in extra-regional Clinical Genetics centres, laboratories and the Italian BWS patients association. All cases were further ascertained through physical exam, medical history and specific molecular tests. The search identified 46 clear-cut cases of BWS born across the 13-year period, providing a prevalence of 1:10 340 live births (95% confidence interval 1:7,752-13,698 live births). Among the 41 patients who underwent molecular tests, 70.7% were positive, showing hypomethylation of the IC2 imprinting center (29.3%), paternal chromosome 11 uniparental disomy (pUPD11, 24.4%), IC1 hypermethylation (14.6%), CDKN1c mutation (2.4%), whereas 29.3% had negative molecular tests. The study provides an approximate BWS prevalence of 1:10,000 live birth, the highest reported to date., (Copyright © 2013 Wiley Periodicals, Inc.)

Noonan syndrome (NS) is an autosomal dominant disorder, characterized by short stature, multiple dysmorphisms and congenital heart defects. A myeloproliferative disorder (NS/MPD), resembling juvenile myelomonocytic leukemia (JMML), is occasionally diagnosed in infants with NS. In the present study, we performed a functional evaluation of the circulating hematopoietic progenitors in a series of NS, NS/MPD and JMML patients. The different functional patterns were compared with the aim to identify a possible NS subgroup worthy of stringent hematological follow-up for an increased risk of MPD development. We studied 27 NS and 5 JMML patients fulfilling EWOG-MDS criteria. The more frequent molecular defects observed in NS were mutations in the PTPN11 and SOS genes. The absolute count of monocytes, circulating CD34+ hematopoietic progenitors, their apoptotic rate and the number of circulating CFU-GMs cultured in the presence of decreasing concentrations or in the absence of granulocyte-macrophage colony-stimulating factor (GM-CSF) were evaluated. All JMML patients showed monocytosis>1,000/µl. Ten out of the 27 NS patients showed monocytosis>1,000/µl, which included the 3 NS/MPD patients. In JMML patients, circulating CD34+ cells were significantly increased (median, 109.8/µl; range, 44-232) with a low rate of apoptosis (median, 2.1%; range, 0.4-12.1%), and circulating CFU-GMs were hyper-responsive to GM-CSF. NS/MPD patients showed the same flow cytometric pattern as the JMML patients (median, CD34+ cells/µl, 205.7; range, 58-1374; median apoptotic rate, 1.4%; range, 0.2-2.4%) and their circulating CFU-GMs were hyper-responsive to GM-CSF. These functional alterations appeared 10 months before the typical clinical manifestations in 1 NS/MPD patient. In NS, the CD34+ absolute cell count and circulating CFU-GMs showed a normal pattern (median CD34+ cells/µl, 4.9; range, 1.3-17.5), whereas the CD34+ cell apoptotic rate was significantly decreased in comparison with the controls (median, 8.6%; range, 0-27.7% vs. median, 17.6%; range, 2.8-49.6%), suggesting an increased CD34+ cell survival. The functional evaluation of circulating hematopoietic progenitors showed specific patterns in NS and NS/MPD. These tests are a reliable integrative tool that, together with clinical data and other hematological parameters, could help detect NS patients with a high risk for a myeloproliferative evolution.

We report a patient with a moderate mental retardation, afebrile seizure, mild dysmorphic features and type 2 diabetes mellitus with mild obesity and metabolic syndrome. Array-CGH analysis revealed a de novo 790-830 kb duplication on chromosome 17p13.1, not reported so far. Among the approximately 50 genes involved in the rearrangement, neuroligin 2 (NLGN2) and ephrin B3 (EFNB3) are candidates for the mental retardation phenotype. NLGN2 may therefore be a novel candidate gene for mental retardation or autistic spectrum disorder, joining other members of the neurexin/neuroligin network. Moreover, GLUT4, a member of the solute carrier family 2, may play a role in the patient's type 2 diabetes., (Copyright © 2012 Elsevier Masson SAS. All rights reserved.)

Acro-dermato-ungual-lacrimal-tooth (ADULT) syndrome is a rare condition belonging to the group of ectodermal dysplasias caused by TP63 mutations. Its clinical phenotype is similar to ectrodactyly-ectodermal dysplasia-cleft lip/palate (EEC) and limb-mammary syndrome (LMS), and differs from these disorders mainly by the absence of cleft lip and/or palate. We report on a 39-year-old patient who was found to be heterozygous for a c.401G > T (p.Gly134Val) de novo mutation of TP63. This patient had the ADULT phenotype associated with cleft palate. Our findings, rather than extend the clinical spectrum of ADULT syndrome, suggest that cleft palate can no longer be considered an element for differential diagnosis for ADULT, EEC, and LMS. Our data, added to other reports on overlapping phenotypes, support the combining of these three phenotypes into a unique entity that we propose to call "ELA syndrome," which is an acronym of ectrodactyly-ectodermal dysplasia-cleft lip and palate, limb-mammary, and ADULT syndromes., (Copyright © 2011 Wiley Periodicals, Inc.)

Noonan syndrome (NS) is among the most common nonchromosomal disorders affecting development and growth. NS is caused by aberrant RAS-MAPK signaling and is genetically heterogeneous, which explains, in part, the marked clinical variability documented for this Mendelian trait. Recently, we and others identified SOS1 as a major gene underlying NS. Here, we explored further the spectrum of SOS1 mutations and their associated phenotypic features. Mutation scanning of the entire SOS1 coding sequence allowed the identification of 33 different variants deemed to be of pathological significance, including 16 novel missense changes and in-frame indels. Various mutation clusters destabilizing or altering orientation of regions of the protein predicted to contribute structurally to the maintenance of autoinhibition were identified. Two previously unappreciated clusters predicted to enhance SOS1's recruitment to the plasma membrane, thus promoting a spatial reorientation of domains contributing to inhibition, were also recognized. Genotype-phenotype analysis confirmed our previous observations, establishing a high frequency of ectodermal anomalies and a low prevalence of cognitive impairment and reduced growth. Finally, mutation analysis performed on cohorts of individuals with nonsyndromic pulmonic stenosis, atrial septal defects, and ventricular septal defects excluded a major contribution of germline SOS1 lesions to the isolated occurrence of these cardiac anomalies., (© 2011 Wiley-Liss, Inc.)

Background: Kabuki syndrome (Niikawa-Kuroki syndrome) is a rare, multiple congenital anomalies/mental retardation syndrome characterized by a peculiar face, short stature, skeletal, visceral and dermatoglyphic abnormalities, cardiac anomalies, and immunological defects. Recently mutations in the histone methyl transferase MLL2 gene have been identified as its underlying cause., Methods: Genomic DNAs were extracted from 62 index patients clinically diagnosed as affected by Kabuki syndrome. Sanger sequencing was performed to analyze the whole coding region of the MLL2 gene including intron-exon junctions. The putative causal and possible functional effect of each nucleotide variant identified was estimated by in silico prediction tools., Results: We identified 45 patients with MLL2 nucleotide variants. 38 out of the 42 variants were never described before. Consistently with previous reports, the majority are nonsense or frameshift mutations predicted to generate a truncated polypeptide. We also identified 3 indel, 7 missense and 3 splice site., Conclusions: This study emphasizes the relevance of mutational screening of the MLL2 gene among patients diagnosed with Kabuki syndrome. The identification of a large spectrum of MLL2 mutations possibly offers the opportunity to improve the actual knowledge on the clinical basis of this multiple congenital anomalies/mental retardation syndrome, design functional studies to understand the molecular mechanisms underlying this disease, establish genotype-phenotype correlations and improve clinical management.

Congenital portosystemic shunts (PSS) are rare vascular anomalies with different gross anatomy. Persistent patent ductus venosus (PDV) represents an uncommon cause of intrahepatic PSS. The diagnosis of this condition may not be obvious because of its wide spectrum of clinical manifestations, ranging from asymptomatic to life-threatening disease. We report the case of three boys with neuropsychological symptoms associated with mild fasting hyperammonemia. An oral protein load allowed the detection of a detoxication defect due to PSS related to PDV. This simple procedure can be worthwhile of attention in patients with mental retardation, behavior disturbances, and learning difficulties after exclusion of common causes of inherited hyperammonemia, namely, urea cycle disorders, organic acidemias, and fatty acid oxidation defects.

Background: Orofacial clefts are common congenital malformations usually characterized by a multifactorial etiology. These heterogeneous defects comprise cleft lip (CL), CL with cleft palate (CL/P), and cleft palate, sometimes observed in recognizable syndromes, with mendelian, chromosomal, or environmental pathogenesis. The Van der Woude syndrome is a mendelian CL/P, accounting for about 2% of all cases and caused by mutations in the interferon regulatory factor 6 (IRF6) gene, located on 1q32.2 chromosome., Objective: Here, we describe a familial case with a novel IRF6 mutation segregating in the maternal line, displaying a highly intrafamilial variable clinical expression., Conclusion: This report emphasizes the role of the clinician in recognizing the clinical variability and the genetic heterogeneity of CL/P.

Noonan syndrome, a developmental disorder characterized by congenital heart defects, reduced growth, facial dysmorphism and variable cognitive deficits, is caused by constitutional dysregulation of the RAS-MAPK signaling pathway. Here we report that germline NRAS mutations conferring enhanced stimulus-dependent MAPK activation account for some cases of this disorder. These findings provide evidence for an obligate dependency on proper NRAS function in human development and growth.

Ectrodactyly-ectodermal dysplasia-cleft lip/palate (EEC) syndrome is an autosomal dominant form of ectodermal dysplasia associated with limb anomalies and orofacial clefting. The TP63 gene has been shown to be the cause of the disease, and some tentative genotype-phenotype correlations have been reported. We describe a familial case of EEC syndrome, diagnosed in two siblings affected by severe ectrodactyly and mild ectodermal dysplasia, without clefting. Moreover, one of the siblings had a history of delayed developmental milestones in the first years of life. Family history revealed mild hand malformations in the father and grandfather, who were not available for clinical evaluation. The TP63 gene molecular study showed in both siblings a heterozygous H208D mutation, which has not been previously reported to our knowledge, suggesting that this molecular lesion is associated with EEC syndrome without orofacial clefting.

Background: Alport syndrome is a clinically and genetically heterogeneous nephropathy characterized by glomerular basement membrane lesions often associated with hearing loss and ocular anomalies. While the X-linked and the autosomal recessive forms are well known, the autosomal dominant form is not well acknowledged., Methods: We have clinically investigated 38 patients with a diagnosis of autosomal dominant Alport syndrome belonging to eight different families. The analysis of the COL4A4 gene was performed by denaturing high performance liquid chromatography and automated DNA sequencing., Results: In our cohort of patients, only 24.3% (9/37) reached end-stage renal disease, at the mean age of 51.2 years. Four patients had hearing loss (13.3%) and none ocular changes. Molecular analysis revealed eight novel private COL4A4 gene mutations: three frameshift, three missense and two splice-site mutations., Conclusions: These data indicate autosomal dominant Alport syndrome as a disease with a low risk of ocular and hearing anomalies but with a significant risk to develop renal failure although at an older age than the X-linked form. We were unable to demonstrate a genotype-phenotype correlation. Altogether, these data make difficult the differential diagnosis with the benign familial haematuria due to heterozygous mutations of COL4A4 and COL4A3, especially in young patients, and with the X-linked form of Alport syndrome in families where only females are affected. A correct diagnosis and prognosis is based on a comprehensive clinical investigation in as many family members as possible associated with a broadly formal genetic analysis of the pedigree.

Background: Intellectual disability affects approximately 1 to 3% of the general population. The etiology is still poorly understood and it is estimated that one-half of the cases are due to genetic factors. Cryptic subtelomeric aberrations have been found in roughly 5 to 7% of all cases., Methods: We performed a subtelomeric FISH analysis on 76 unrelated children with normal standard karyotype ascertained by developmental delay or intellectual disability, associated with congenital malformations, and/or facial dysmorphisms., Results: Ten cryptic chromosomal anomalies have been identified in the whole cohort (13,16%), 8 in the group of patients characterized by developmental delay or intellectual disability associated with congenital malformations and facial dysmorphisms, 2 in patients with developmental delay or intellectual disability and facial dysmorphisms only., Conclusion: We demonstrate that a careful clinical examination is a very useful tool for pre-selection of patients for genomic analysis, clearly enhancing the chromosomal anomaly detection rate. Clinical features of most of these patients are consistent with the corresponding emerging chromosome phenotypes, pointing out these new clinical syndromes associated with specific genomic imbalances.

Noonan, LEOPARD, and cardiofaciocutaneous syndromes (NS, LS, and CFCS) are developmental disorders with overlapping features including distinctive facial dysmorphia, reduced growth, cardiac defects, skeletal and ectodermal anomalies, and variable cognitive deficits. Dysregulated RAS-mitogen-activated protein kinase (MAPK) signal traffic has been established to represent the molecular pathogenic cause underlying these conditions. To investigate the phenotypic spectrum and molecular diversity of germline mutations affecting BRAF, which encodes a serine/threonine kinase functioning as a RAS effector frequently mutated in CFCS, subjects with a diagnosis of NS (N=270), LS (N=6), and CFCS (N=33), and no mutation in PTPN11, SOS1, KRAS, RAF1, MEK1, or MEK2, were screened for the entire coding sequence of the gene. Besides the expected high prevalence of mutations observed among CFCS patients (52%), a de novo heterozygous missense change was identified in one subject with LS (17%) and five individuals with NS (1.9%). Mutations mapped to multiple protein domains and largely did not overlap with cancer-associated defects. NS-causing mutations had not been documented in CFCS, suggesting that the phenotypes arising from germline BRAF defects might be allele specific. Selected mutant BRAF proteins promoted variable gain of function of the kinase, but appeared less activating compared to the recurrent cancer-associated p.Val600Glu mutant. Our findings provide evidence for a wide phenotypic diversity associated with mutations affecting BRAF, and occurrence of a clinical continuum associated with these molecular lesions., ((c) 2009 Wiley-Liss, Inc.)

Aim: PHACES syndrome is a neurocutaneous condition characterized by the coexistence of large facial haemangiomas and at least one feature among posterior fossa malformations, cardiac and arterial anomalies, eye defects and sternal clefting. We review and discuss the phenotypes and the endocrine aspects of PHACES syndrome, hypothesizing that endocrine anomalies, although rare, could be considered as feature of the disease., Methods: We described four new cases representative of the wide variable phenotype of this syndrome, commenting on the possible phenotypic expression., Results: Two children displayed endocrine anomalies, sporadically described among PHACES subjects. One of them developed a transient hyperthyreotropinemia induced by interferon alpha-2alpha treatment for a giant facial haemangioma, while the second presented with congenital hypothyroidism with an in situ thyroid gland, a trait previously unreported in the syndrome., Conclusion: PHACES syndrome has a wide variable phenotypic expression and endocrine anomalies, especially hypothyroidism, may represent a trait of the syndrome and should be always investigated.

Noonan syndrome (NS, OMIM 163950) is an autosomal dominant disorder, with a prevalence at birth of 1:1000-1:2500 live births, characterized by short stature, facial and skeletal dysmorphisms, cardiovascular defects and haematological anomalies. Missense mutations of PTPN11 gene account for approximately 50% of NS cases, while molecular lesions of other genes of the RAS/MAPK pathway -KRAS, SOS1 and RAF1 - play a minor role in the molecular pathogenesis of the disease. Forty patients were enrolled in the study with a PTPN11 mutation detection rate of 31.5%, including a novel missense mutation, Phe285Ile, in a familial case with high intrafamilial phenotypic variability. All patients negative for PTPN11 mutations were further screened for mutations of the KRAS, SOS1, and RAF1 genes, revealing a Thr266Lys substitution in SOS1 in a single patient, a newborn with a subtle phenotype, characterized by facial dysmorphisms and a mild pulmonic stenosis.

Background: Differentially methylated regions (DMRs) are associated with many imprinted genes. In mice methylation at a DMR upstream of the H19 gene known as the Imprint Control region (IC1) is acquired in the male germline and influences the methylation status of DMRs 100 kb away in the adjacent Insulin-like growth factor 2 (Igf2) gene through long-range interactions. In humans, germline-derived or post-zygotically acquired imprinting defects at IC1 are associated with aberrant activation or repression of IGF2, resulting in the congenital growth disorders Beckwith-Wiedemann (BWS) and Silver-Russell (SRS) syndromes, respectively. In Wilms tumour and colorectal cancer, biallelic expression of IGF2 has been observed in association with loss of methylation at a DMR in IGF2. This DMR, known as DMR0, has been shown to be methylated on the silent maternal IGF2 allele presumably with a role in repression. The effect of IGF2 DMR0 methylation changes in the aetiology of BWS or SRS is unknown., Methodology/principal Findings: We analysed the methylation status of the DMR0 in BWS, SRS and Wilms tumour patients by conventional bisulphite sequencing and pyrosequencing. We show here that, contrary to previous reports, the IGF2 DMR0 is actually methylated on the active paternal allele in peripheral blood and kidney. This is similar to the IC1 methylation status and is inconsistent with the proposed silencing function of the maternal IGF2 allele. Beckwith-Wiedemann and Silver-Russell patients with IC1 methylation defects have similar methylation defects at the IGF2 DMR0, consistent with IC1 regulating methylation at IGF2 in cis. In Wilms tumour, however, methylation profiles of IC1 and IGF2 DMR0 are indicative of methylation changes occurring on both parental alleles rather than in cis., Conclusions/significance: These results support a model in which DMR0 and IC1 have opposite susceptibilities to global hyper and hypomethylation during tumorigenesis independent of the parent of origin imprint. In contrast, during embryogenesis DMR0 is methylated or demethylated according to the germline methylation imprint at the IC1, indicating different mechanisms of imprinting loss in neoplastic and non-neoplastic cells.

Williams-Beuren syndrome (WS) is a rare multi-system genomic disorder, caused by 7q11.23 microdeletion with a prevalence of 1/7500-1/20,000 live births. Clinical phenotype includes typical facial dysmorphism (elfin face), mental retardation associated with a peculiar neuropsychological profile and congenital heart defects. We investigated 22 WS patients (mean age of 9.7 years, range 1 day to 39 years) with a multi-specialist follow-up protocol comprehensive of neuropsychological, cardiologic, nephrologic, ophthalmologic, endocrinologic, gastroenterologic, odontostomatologic and orthopaedic evaluations. The mean age at diagnosis was 5.38 years, being 1.02 years when genetic evaluation was requested for congenital heart defects (CHD) and 10.68 years in case of mental retardation and/or abnormal neuropsychological profile without an evident CHD. All patients showed facial dysmorphisms, with supravalvular aortic stenosis (SVAS) as the most common cardiovascular anomaly (12/22), followed by peripheral pulmonary stenosis (9/22); interestingly, in one patient we detected a total anomalous pulmonary venous return (TAPVR), confirming the possible association of this rare CHD with WS. Hypertension was detected by 24-h ambulatory blood pressure monitoring in 7/22 cases. A cognitive assessment was performed in 13 patients older than 6 years, showing various degrees of mental retardation in 12 and a normal intelligence quotient (IQ) in a single patient; evaluation of developmental milestones revealed various grades of developmental delay in all the patients younger than 6 years. Chiari malformation type 1 was found in 3 patients. Our study underlines a remarkable diagnostic delay in patients who present to genetic evaluation because of mental retardation and/or peculiar neuropsychological profile lacking an evident cardiopathy and confirms the multi-systemic nature of WS leading to a high clinical presentation's variability and complex follow-up strategies.

Nucleotide excision repair (NER) is a genome caretaker mechanism responsible for removing helix-distorting DNA lesions, most notably ultraviolet photodimers. Inherited defects in NER result in profound photosensitivity and the cancer-prone syndrome xeroderma pigmentosum (XP) or two progeroid syndromes: Cockayne and trichothiodystrophy syndromes. The heterodimer ERCC1-XPF is one of two endonucleases required for NER. Mutations in XPF are associated with mild XP and rarely with progeria. Mutations in ERCC1 have not been reported. Here, we describe the first case of human inherited ERCC1 deficiency. Patient cells showed moderate hypersensitivity to ultraviolet rays and mitomycin C, yet the clinical features were very severe and, unexpectedly, were compatible with a diagnosis of cerebro-oculo-facio-skeletal syndrome. This discovery represents a novel complementation group of patients with defective NER. Further, the clinical severity, coupled with a relatively mild repair defect, suggests novel functions for ERCC1.

The imprinted expression of the IGF2 and H19 genes is controlled by the Imprinting Centre 1 (IC1) at chromosome 11p15.5. This is a methylation-sensitive chromatin insulator that works by binding the zinc-finger protein CTCF in a parent-specific manner. Microdeletions abolishing some of the CTCF target sites (CTSs) of IC1 have been associated with the Beckwith-Wiedemann syndrome (BWS). However, the link between these mutations and the molecular and clinical phenotypes was debated. We have identified two novel families with IC1 deletions, in which individuals with the clinical features of the BWS are present in multiple generations. By analysing the methylation pattern at the IGF2-H19 locus together with the clinical phenotypes in the individuals with maternal and those with paternal transmission of five different deletions, we demonstrate that maternal transmission of 1.4-1.8 kb deletions in the IC1 region co-segregates with the hypermethylation of the residual CTSs and BWS phenotype with complete penetrance, whereas normal phenotype is observed upon paternal transmission. Although gene expression could not be assayed in all cases, the methylation detected at the IGF2 DMR2 and H19 promoter suggests that IC1 hypermethylation is consistently associated with biallelic activation of IGF2 and biallelic silencing of H19. Comparison of these deletions with a 2.2 kb one previously reported by another group indicates that the spacing of the CTSs on the deleted allele is critical for the gain of the abnormal methylation and penetrance of the clinical phenotype. Furthermore, we observe that the hypermethylation resulting from the deletions is always mosaic, suggesting that the epigenetic defect at the IGF2-H19 locus is established post-zygotically and may cause body asymmetry and heterogeneity of the clinical phenotype. Finally, the IC1 microdeletions are associated with a high incidence of Wilms' tumour, making their molecular diagnosis particularly important for genetic counselling and tumour surveillance at follow-up.

The overgrowth- and tumor-associated Beckwith-Wiedemann syndrome results from dysregulation of imprinted genes on chromosome 11p15.5. Here we show that inherited microdeletions in the H19 differentially methylated region (DMR) that abolish two CTCF target sites cause this disease. Maternal transmission of the deletions results in hypermethylation of the H19 DMR, biallelic IGF2 expression, H19 silencing and Beckwith-Wiedemann syndrome, indicative of loss of function of the IGF2-H19 imprinting control element.

We report on a girl with congenital hypoplastic anaemia, "coarse" face, generalized hypertrichosis with scalp hypotrichosis, short fifth finger, hypoplastic toenails, and mental retardation. A sister of the proposita, who died at the age of 1 year, had severe congenital anaemia, hypoplastic fingernails, low birth weight, failure to thrive, and repeated upper respiratory tract infections. Based on family history, we suspect that hypoplastic anaemia and the same multiple congenital anomalies-mental retardation syndrome (MCA/MR) were also present in this sister. To the best of our knowledge, this patient represents the first report of congenital hypoplastic anaemia and such a complex MCA/MR syndrome, probably inherited as an autosomal recessive trait., (Copyright 1999 Wiley-Liss, Inc.)

We describe a girl with Niikawa-Kuroki (Kabuki) syndrome (NKS) with conical incisors, hypodontia, hypoplastic nails, and brittle hair. Abnormal teeth are common in NKS and support a hypothesis of autosomal dominant inheritance of the syndrome [Halal et al., 1989; Silengo et al., 1996]. Hair abnormalities have never been investigated in NKS. The ectodermal involvement in NKS could represent an important clue for the understanding of the pathogenesis of this syndrome.

Four unrelated cases of congenital diaphragmatic hernia associated with ipsilateral upper limb reduction defects were reported by McCredie and Reid in 1978 (J Pediatr 92: 762-765). As contiguous segments of the cervical neural crest are involved in the development of diaphragm and arms, the authors suggested that an early injury to the cervical neural crest might be the common underlying pathogenesis. We describe here a further example of this malformation complex: a newborn with a left posterolateral diaphragmatic hernia associated with ipsilateral thumb hypoplasia.

In 1982, Nadol & Burgess reported a new syndrome of cataract and progressive sensorineural hearing loss, inherited in an autosomal dominant fashion. Extensive histopathologic studies of the inner ear of the proband revealed severe cochleosaccular degeneration. No other sporadic or familial cases of such a genetic syndrome have subsequently been described. We report here a second family in which the syndrome of cataract and progressive sensorineural deafness is observed in eight members, and is inherited according to an autosomal dominant pattern.

A syndrome of ocular and cutaneous hypopigmentation, severe mental retardation with spastic tetraplegia and athetosis was first observed by Cross in three siblings of an inbred Amish family. Since then, seven other patients, three sporadic and four with familial recurrence, have been reported in the literature, confirming the autosomal recessive inheritance. The clinical spectrum of the syndrome has been expanded to include true developmental defects of the CNS such as cystic malformation of the posterior fossa of the Dandy-Walker type. We report a new case of Cross syndrome.