0000000000191490
AUTHOR
Joris Andrieux
Further delineation of eye manifestations in homozygous 15q13.3 microdeletions including TRPM1: a differential diagnosis of ceroid lipofuscinosis.
The 15q13.3 heterozygous microdeletion is a fairly common microdeletion syndrome with marked clinical variability and incomplete penetrance. The average size of the deletion, which comprises six genes including CHRNA7, is 1.5 Mb. CHRNA7 has been identified as the gene responsible for the neurological phenotype in this microdeletion syndrome. Only seven patients with a homozygous microdeletion that includes at least CHRNA7, and is inherited from both parents have been described in the literature. The aim of this study was to further describe the distinctive eye manifestations from the analysis in the three French patients diagnosed with the classical 1.5 Mb homozygous microdeletion. Patients…
New insights into the pathogenesis of Beckwith-Wiedemann and Silver-Russell syndromes: contribution of small copy number variations to 11p15 imprinting defects.
International audience; The imprinted 11p15 region is organized in two domains, each of them under the control of its own imprinting control region (ICR1 for the IGF2/H19 domain and ICR2 for the KCNQ1OT1/CDKN1C domain). Disruption of 11p15 imprinting results in two fetal growth disorders with opposite phenotypes: the Beckwith-Wiedemann (BWS) and the Silver-Russell (SRS) syndromes. Various 11p15 genetic and epigenetic defects have been demonstrated in BWS and SRS. Among them, isolated DNA methylation defects account for approximately 60% of patients. To investigate whether cryptic copy number variations (CNVs) involving only part of one of the two imprinted domains account for 11p15 isolated…
9q33.3q34.11 microdeletion: new contiguous gene syndrome encompassing STXBP1, LMX1B and ENG genes assessed using reverse phenotyping
International audience; The increasing use of array-CGH in malformation syndromes with intellectual disability could lead to the description of new contiguous gene syndrome by the analysis of the gene content of the microdeletion and reverse phenotyping. Thanks to a national and international call for collaboration by Achropuce and Decipher, we recruited four patients carrying de novo overlapping deletions of chromosome 9q33.3q34.11, including the STXBP1, the LMX1B and the ENG genes. We restrained the selection to these three genes because the effects of their haploinsufficency are well described in the literature and easily recognizable clinically. All deletions were detected by array-CGH …
Rare variants in the genetic background modulate cognitive and developmental phenotypes in individuals carrying disease-associated variants
Purpose: To assess the contribution of rare variants in the genetic background toward variability of neurodevelopmental phenotypes in individuals with rare copy-number variants (CNVs) and gene-disruptive variants. Methods: We analyzed quantitative clinical information, exome sequencing, and microarray data from 757 probands and 233 parents and siblings who carry disease-associated variants. Results: The number of rare likely deleterious variants in functionally intolerant genes (“other hits”) correlated with expression of neurodevelopmental phenotypes in probands with 16p12.1 deletion (n=23, p=0.004) and in autism probands carrying gene-disruptive variants (n=184, p=0.03) compared with thei…
12p13.33 microdeletion including ELKS/ERC1, a new locus associated with childhood apraxia of speech.
Speech sound disorders are heterogeneous conditions, and sporadic and familial cases have been described. However, monogenic inheritance explains only a small proportion of such disorders, in particular in cases with childhood apraxia of speech (CAS). Deletions of <5 Mb involving the 12p13.33 locus is one of the least commonly deleted subtelomeric regions. Only four patients have been reported with such a deletion diagnosed with fluorescence in situ hybridisation telomere analysis or array CGH. To further delineate this rare microdeletional syndrome, a French collaboration together with a search in the Decipher database allowed us to gather nine new patients with a 12p13.33 subtelomeric or …
Genetic and phenotypic dissection of 1q43q44 microdeletion syndrome and neurodevelopmental phenotypes associated with mutations in ZBTB18 and HNRNPU
Subtelomeric 1q43q44 microdeletions cause a syndrome associating intellectual disability, microcephaly, seizures and anomalies of the corpus callosum. Despite several previous studies assessing genotype-phenotype correlations, the contribution of genes located in this region to the specific features of this syndrome remains uncertain. Among those, three genes, AKT3, HNRNPU and ZBTB18 are highly expressed in the brain and point mutations in these genes have been recently identified in children with neurodevelopmental phenotypes. In this study, we report the clinical and molecular data from 17 patients with 1q43q44 microdeletions, four with ZBTB18 mutations and seven with HNRNPU mutations, an…
Split hand/foot malformation with long-bone deficiency andBHLHA9duplication: report of 13 new families
Split hand/foot malformation (SHFM) with long-bone deficiency (SHFLD, MIM#119100) is a rare condition characterized by SHFM associated with long-bone malformation usually involving the tibia. Previous published data reported several unrelated patients with 17p13.3 duplication and SHFLD. Recently, the minimal critical region had been reduced, suggesting that BHLHA9 copy number gains are associated with this limb defect. Here, we report on 13 new families presenting with ectrodactyly and harboring a BHLHA9 duplication.
Molecular characterization of 39 de novo sSMC: contribution to prognosis and genetic counselling, a prospective study.
Small supernumerary marker chromosomes (sSMCs) are structurally abnormal chromosomes that cannot be characterized by karyotype. In many prenatal cases of de novo sSMC, the outcome of pregnancy is difficult to predict because the euchromatin content is unclear. This study aimed to determine the presence or absence of euchromatin material of 39 de novo prenatally ascertained sSMC by array-comparative genomic hybridization (array-CGH) or single nucleotide polymorphism (SNP) array. Cases were prospectively ascertained from the study of 65,000 prenatal samples [0.060%; 95% confidence interval (CI), 0.042-0.082]. Array-CGH showed that 22 markers were derived from non-acrocentric markers (56.4%) a…
Rare variants in the genetic background modulate the expressivity of neurodevelopmental disorders
AbstractPurposeTo assess the contribution of rare variants in the genetic background towards variability of neurodevelopmental phenotypes in individuals with rare copy-number variants (CNVs) and gene-disruptive mutations.MethodsWe analyzed quantitative clinical information, exome-sequencing, and microarray data from 757 probands and 233 parents and siblings who carry disease-associated mutations.ResultsThe number of rare secondary mutations in functionally intolerant genes (second-hits) correlated with the expressivity of neurodevelopmental phenotypes in probands with 16p12.1 deletion (n=23, p=0.004) and in probands with autism carrying gene-disruptive mutations (n=184, p=0.03) compared to …
Incomplete penetrance and phenotypic variability of 6q16 deletions including SIM1.
International audience; 6q16 deletions have been described in patients with a Prader-Willi-like (PWS-like) phenotype. Recent studies have shown that certain rare single-minded 1 (SIM1) loss-of-function variants were associated with a high intra-familial risk for obesity with or without features of PWS-like syndrome. Although SIM1 seems to have a key role in the phenotype of patients carrying 6q16 deletions, some data support a contribution of other genes, such as GRIK2, to explain associated behavioural problems. We describe 15 new patients in whom de novo 6q16 deletions were characterised by comparative genomic hybridisation or single-nucleotide polymorphism (SNP) array analysis, including…