A large, ten-generation family with autosomal dominant preaxial polydactyly/triphalangeal thumb: Historical, clinical, genealogical, and molecular studies

We present a large, ten-generation family of 273 individuals with 84 people having preaxial polydactyly/triphalangeal thumb due to a pathogenic variant in the zone of polarizing activity regulatory sequence (ZRS) within the exon 5 of LMBR1. The causative change maps to position 396 of the ZRS, located at position c.423 + 4909C > T (chr7:156791480; hg38; LMBR1 ENST00000353442.10; rs606231153 NG_009240.2) in the intron 5 of LMBR1. The first affected individual with the disorder was traced back to mid-1700, when some settlers and workers established in Cervera de Buitrago, a small village about 82 km North to Madrid. Clinical and radiological studies of most of the affected members have been performed for 42 years (follow-up of the family by LFGA). Molecular studies have confirmed a pathogenic variant in the ZRS that segregates in this family. To the best of our knowledge, this is the largest family with preaxial polydactyly/triphalangeal thumb reported so far.Instituto de Salud Carlos III, Grant/Award Number: PI20/0105

Phenotypic variation in patients with homozygous c.1678G>T mutation in EVC gene: Report of two mexican families with Ellis-van Creveld syndrome

[Background]: Ellis-van Creveld syndrome is an autosomal recessive chondro-ectodermal dysplasia characterized by disproportionate short stature, limb shortening, narrow chest, postaxial polydactyly and dysplastic nails and teeth. In addition, 60% of cases present congenital heart defects. Ellis-van Creveld syndrome is predominantly caused by mutations in the EVC or EVC2 (4p16) genes, with only a few cases caused by mutations in WDR35.[Case Report]: Here, we report on two Mexican families with patients diagnosed with Ellis-van Creveld syndrome. Family 1 includes four patients: three females of 15, 18, and 23 years of age and a 7-year old male. Family 2 has only one affected newborn male. All patients exhibited multiple features including hypodontia, dysplastic teeth, extra frenula, mild short stature, distal limb shortening, postaxial polydactyly of hands and feet, nail dystrophy, and knee joint abnormalities. Only two patients had an atrial septal defect. In all cases, molecular analysis by Sanger sequencing identified the same homozygous mutation in exon 12 of EVC, c.1678G>T, which leads to a premature stop codon.[Conclusions]: The mutation c.1678G>T has been previously reported in another Mexican patient and it appears to be a recurrent mutation in Mexico which could represent a founder mutation. The large number of patients in this case allows the clinical variability and spectrum of manifestations present in individuals with Ellis-van Creveld syndrome even if they carry the same homozygous mutation in a same family.Peer reviewe

Identification of a mutation causing deficient BMP1/mTLD proteolytic activity in autosomal recessive osteogenesis imperfecta

Herein, we have studied a consanguineous Egyptian family with two children diagnosed with severe autosomal recessive osteogenesis imperfecta (AR-OI) and a large umbilical hernia. Homozygosity mapping in this family showed lack of linkage to any of the previously known AR-OI genes, but revealed a 10.27 MB homozygous region on chromosome 8p in the two affected sibs, which comprised the procollagen I C-terminal propeptide (PICP) endopeptidase gene BMP1. Mutation analysis identified both patients with a Phe249Leu homozygous missense change within the BMP1 protease domain involving a residue, which is conserved in all members of the astacin group of metalloproteases. Type I procollagen analysis in supernatants from cultured fibroblasts demonstrated abnormal PICP processing in patient-derived cells consistent with the mutation causing decreased BMP1 function. This was further confirmed by overexpressing wild type and mutant BMP1 longer isoform (mammalian Tolloid protein [mTLD]) in NIH3T3 fibroblasts and human primary fibroblasts. While overproduction of normal mTLD resulted in a large proportion of proα1(I) in the culture media being C-terminally processed, proα1(I) cleavage was not enhanced by an excess of the mutant protein, proving that the Phe249Leu mutation leads to a BMP1/mTLD protein with deficient PICP proteolytic activity. We conclude that BMP1 is an additional gene mutated in AR-OI

Identification of a Frameshift Mutation in Osterix in a Patient with Recessive Osteogenesis Imperfecta

Osteogenesis imperfecta, or “brittle bone disease,” is a type I collagen-related condition associated with osteoporosis and increased risk of bone fractures. Using a combination of homozygosity mapping and candidate gene approach, we have identified a homozygous single base pair deletion (c.1052delA) in SP7/Osterix (OSX) in an Egyptian child with recessive osteogenesis imperfecta. The clinical findings from this patient include recurrent fractures, mild bone deformities, delayed tooth eruption, normal hearing, and white sclera. OSX encodes a transcription factor containing three Cys2-His2 zinc-finger DNA-binding domains at its C terminus, which, in mice, has been shown to be essential for bone formation. The frameshift caused by the c.1052delA deletion removes the last 81 amino acids of the protein, including the third zinc-finger motif. This finding adds another locus to the spectrum of genes associated with osteogenesis imperfecta and reveals that SP7/OSX also plays a key role in human bone development

Characterization of a 8q21.11 microdeletion syndrome associated with intellectual disability and a recognizable phenotype

We report eight unrelated individuals with intellectual disability and overlapping submicroscopic deletions of 8q21.11 (0.66-13.55 Mb in size). The deletion was familial in one and simplex in seven individuals. The phenotype was remarkably similar and consisted of a round face with full cheeks, a high forehead, ptosis, cornea opacities, an underdeveloped alae, a short philtrum, a cupid's bow of the upper lip, down-turned corners of the mouth, micrognathia, low-set and prominent ears, and mild finger and toe anomalies (camptodactyly, syndactyly, and broadening of the first rays). Intellectual disability, hypotonia, decreased balance, sensorineural hearing loss, and unusual behavior were frequently observed. A high-resolution oligonucleotide array showed different proximal and distal breakpoints in all of the individuals. Sequencing studies in three of the individuals revealed that proximal and distal breakpoints were located in unique sequences with no apparent homology. The smallest region of overlap was a 539.7 kb interval encompassing three genes: a Zinc Finger Homeobox 4 (ZFHX4), one microRNA of unknown function, and one nonfunctional pseudogen. ZFHX4 encodes a transcription factor expressed in the adult human brain, skeletal muscle, and liver. It has been suggested as a candidate gene for congenital bilateral isolated ptosis. Our results suggest that the 8q21.11 submicroscopic deletion represents a clinically recognizable entity and that a haploinsufficient gene or genes within the minimal deletion region could underlie this syndrom

Array CGH Analysis of Paired Blood and Tumor Samples from Patients with Sporadic Wilms Tumor

Submitted by sandra infurna ([email protected]) on 2016-03-01T16:49:50Z No. of bitstreams: 1 fernando2_vargas_etal_IOC_2015.pdf: 477665 bytes, checksum: 7b0ca95990e0ab5295b7e7bec530658b (MD5)Approved for entry into archive by sandra infurna ([email protected]) on 2016-03-01T17:11:58Z (GMT) No. of bitstreams: 1 fernando2_vargas_etal_IOC_2015.pdf: 477665 bytes, checksum: 7b0ca95990e0ab5295b7e7bec530658b (MD5)Made available in DSpace on 2016-03-01T17:11:58Z (GMT). No. of bitstreams: 1 fernando2_vargas_etal_IOC_2015.pdf: 477665 bytes, checksum: 7b0ca95990e0ab5295b7e7bec530658b (MD5) Previous issue date: 2015Instituto Nacional de Câncer. Divisão de Genética. Rio de Janeiro, RJ, Brasil.Hospital Universitario La Paz. Institute of Medical and Molecular Genetics (INGEMM)-IdiPAZ. Section of Functional and Structural Genomics. Madrid, Spain.Hospital Universitario La Paz. Institute of Medical and Molecular Genetics (INGEMM)-IdiPAZ. Section of Functional and Structural Genomics. Madrid, Spain.Hospital Universitario La Paz. Institute of Medical and Molecular Genetics (INGEMM)-IdiPAZ. Section of Functional and Structural Genomics. Madrid, Spain / CIBERER. Centro de Investigación Biomédica en Red de Enfermedades Raras, Madrid, Spain.Hospital Universitario La Paz. Institute of Medical and Molecular Genetics (INGEMM)-IdiPAZ. Section of Functional and Structural Genomics. Madrid, Spain / CIBERER. Centro de Investigación Biomédica en Red de Enfermedades Raras, Madrid, Spain.Hospital Universitario La Paz. Institute of Medical and Molecular Genetics (INGEMM)-IdiPAZ. Section of Functional and Structural Genomics. Madrid, Spain.Hospital Universitario La Paz. Institute of Medical and Molecular Genetics (INGEMM)-IdiPAZ. Section of Functional and Structural Genomics. Madrid, Spain.Instituto Nacional de Câncer. Divisão de Patologia. Rio de Janeiro, RJ, Brasil.GT-CSGP Working Group.Institute of Medical and Molecular Genetics (INGEMM)-IdiPAZ. Hospital Universitario La Paz. Section of Clinical Genetics, . Madrid, Spain.CIBERER. Centro de Investigación Biomédica en Red de Enfermedades Raras, Madrid, Spain / Institute of Medical and Molecular Genetics (INGEMM)-IdiPAZ. Hospital Universitario La Paz. Section of Clinical Genetics, . Madrid, Spain.Universidade Federal do Rio de Janeiro. Departamento de Genética. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Epidemiologia de Malformações Congênitas. Rio de Janeiro, RJ, Brasil.Instituto Nacional de Câncer. Divisão de Genética. Rio de Janeiro, RJ, Brasil / Universidade Federal do Rio de Janeiro. Departamento de Genética. Rio de Janeiro, RJ, Brasil.Hospital Universitario La Paz. Institute of Medical and Molecular Genetics (INGEMM)-IdiPAZ. Section of Functional and Structural Genomics. Madrid, Spain / CIBERER. Centro de Investigación Biomédica en Red de Enfermedades Raras, Madrid, Spain.Wilms tumor (WT), the most common cancer of the kidney in infants and children, has a complex etiology that is still poorly understood. Identification of genomic copy number variants (CNV) in tumor genomes provides a better understanding of cancer development which may be useful for diagnosis and therapeutic targets. In paired blood and tumor DNA samples from 14 patients with sporadic WT, analyzed by aCGH, 22% of chromosome abnormalities were novel. All constitutional alterations identified in blood were segmental (in 28.6% of patients) and were also present in the paired tumor samples. Two segmental gains (2p21 and 20q13.3) and one loss (19q13.31) present in blood had not been previously described in WT. We also describe, for the first time, a small, constitutive partial gain of 3p22.1 comprising 2 exons of CTNNB1, a gene associated to WT. Among somatic alterations, novel structural chromosomal abnormalities were found, like gain of 19p13.3 and 20p12.3, and losses of 2p16.1-p15, 4q32.5-q35.1, 4q35.2-q28.1 and 19p13.3. Candidate genes included in these regions might be constitutively (SIX3, SALL4) or somatically (NEK1, PIAS4, BMP2) operational in the development and progression of WT. To our knowledge this is the first report of CNV in paired blood and tumor samples in sporadic WT

CLAPO syndrome: identification of somatic activating PIK3CA mutations and delineation of the natural history and phenotype

[Purpose]: CLAPO syndrome is a rare vascular disorder characterized by capillary malformation of the lower lip, lymphatic malformation predominant on the face and neck, asymmetry, and partial/generalized overgrowth. Here we tested the hypothesis that, although the genetic cause is not known, the tissue distribution of the clinical manifestations in CLAPO seems to follow a pattern of somatic mosaicism.[Methods]: We clinically evaluated a cohort of 13 patients with CLAPO and screened 20 DNA blood/tissue samples from 9 patients using high-throughput, deep sequencing.[Results]: We identified five activating mutations in the PIK3CA gene in affected tissues from 6 of the 9 patients studied; one of the variants (NM_006218.2:c.248T>C; p.Phe83Ser) has not been previously described in developmental disorders.[Conclusion]: We describe for the first time the presence of somatic activating PIK3CA mutations in patients with CLAPO. We also report an update of the phenotype and natural history of the syndrome.This research was supported by the project “Genetics of vascular and lymphatic malformations” financed with funds donated by Asociación Ultrafondo and Villareal FC, cofinanced by project IP-17 from the funding call “Todos Somos Raros” (Telemaraton TVE promoted by Fundación Isabel Gemio, Federación ASEM, and Federación Española de Enfermedades Raras), cofinanced by the Instituto de Salud Carlos III, FEDER FUNDS FIS PI15/01481, and IIS-Fundación Jiménez Díaz UAM Genome Medicine Chair.Peer reviewe

Specific variants in WDR35 cause a distinctive form of ellis-van creveld syndrome by disrupting the recruitment of the evc complex and smo into the cilium

© The Author 2015. Published by Oxford University Press. All rights reserved. Most patients with Ellis-van Creveld syndrome (EvC) are identified with pathogenic changes in EVC or EVC2, however further genetic heterogeneity has been suggested. In this report we describe pathogenic splicing variants in WDR35, encoding retrograde intraflagellar transport protein 121 (IFT121), in three families with a clinical diagnosis of EvC but having a distinctive phenotype. To understand why WDR35 variants result in EvC, we analysed EVC, EVC2 and Smoothened (SMO) in IFT-A deficient cells. We found that the three proteins failed to localize to Wdr35 -/- cilia, but not to the cilium of the IFT retrograde motor mutant Dync2h1 -/- , indicating that IFT121 is specifically required for their entry into the ciliary compartment. Furthermore expression of Wdr35 disease cDNAs in Wdr35 -/- fibroblasts revealed that the newly identified variants lead to Hedgehog signalling defects resembling those of Evc -/- and Evc2 -/- mutants. Together our data indicate that splicing variants in WDR35, and possibly in other IFT-A components, underlie a number of EvC cases by disrupting targeting of both the EvC complex and SMO to cilia