0000000000149960
AUTHOR
Sebastien Moutton
showing 14 related works from this author
Variants of human CLDN9 cause mild to profound hearing loss
2021
Hereditary deafness is clinically and genetically heterogeneous. We investigated deafness segregating as a recessive trait in two families. Audiological examinations revealed an asymmetric mild to profound hearing loss with childhood or adolescent onset. Exome sequencing of probands identified a homozygous c.475G>A;p.(Glu159Lys) variant of CLDN9 (NM_020982.4) in one family and a homozygous c.370_372dupATC;p.(Ile124dup) CLDN9 variant in an affected individual of a second family. Claudin 9 (CLDN9) is an integral membrane protein and constituent of epithelial bicellular tight junctions that form semi-permeable, paracellular barriers between inner ear perilymphatic and endolymphatic compartment…
Phenotypic and biochemical analysis of an international cohort of individuals with variants in NAA10 and NAA15.
2019
Abstract N-alpha-acetylation is one of the most common co-translational protein modifications in humans and is essential for normal cell function. NAA10 encodes for the enzyme NAA10, which is the catalytic subunit in the N-terminal acetyltransferase A (NatA) complex. The auxiliary and regulatory subunits of the NatA complex are NAA15 and Huntington-interacting protein (HYPK), respectively. Through a genotype-first approach with exome sequencing, we identified and phenotypically characterized 30 individuals from 30 unrelated families with 17 different de novo or inherited, dominantly acting missense variants in NAA10 or NAA15. Clinical features of affected individuals include variable levels…
Generation of an iPSC line (UNINAi001-A) from a girl with neonatal-onset epilepsy and non-syndromic intellectual disability carrying the homozygous K…
2021
Abstract Heterozygous variants in the KCNQ3 gene cause epileptic and/or developmental disorders of varying severity. Here we describe the generation of induced pluripotent stem cells (iPSCs) from a 9-year-old girl with pharmacodependent neonatal-onset epilepsy and intellectual disability who carry a homozygous single-base duplication in exon 12 of KCNQ3 (NM_004519.3: KCNQ3 c.1599dup; KCNQ3 p.PHE534ILEfs*15), and from a non-carrier brother of the proband. For iPSC generation, non-integrating episomal plasmid vectors were used to transfect fibroblasts isolated from skin biopsies. The obtained iPSC lines had a normal karyotype, showed embryonic stem cell-like morphology, expressed pluripotency…
Variant recurrence in neurodevelopmental disorders: the use of publicly available genomic data identifies clinically relevant pathogenic missense var…
2019
Next-generation sequencing has revealed the major impact of de novo variants (DNVs) in developmental disorders (DD) such as intellectual disability, autism, and epilepsy. However, a substantial fraction of these predicted pathogenic DNVs remains challenging to distinguish from background DNVs, notably the missense variants acting via nonhaploinsufficient mechanisms on specific amino acid residues. We hypothesized that the detection of the same missense variation in at least two unrelated individuals presenting with a similar phenotype could be a powerful approach to reveal novel pathogenic variants. We looked for variations independently present in both our database of >1200 solo exomes and…
Hearing impairment as an early sign of alpha-mannosidosis in children with a mild phenotype: Report of seven new cases.
2019
Alpha-mannosidosis (AM) is a very rare (prevalence: 1/500000 births) autosomal recessive lysosomal storage disorder. It is characterized by multi-systemic involvement associated with progressive intellectual disability, hearing loss, skeletal anomalies, and coarse facial features. The spectrum is wide, from very severe and lethal to a milder phenotype that usually progresses slowly. AM is caused by a deficiency of lysosomal alpha-mannosidase. A diagnosis can be established by measuring the activity of lysosomal alpha-mannosidase in leucocytes and screening for abnormal urinary excretion of mannose-rich oligosaccharides. Genetic confirmation is obtained with the identification of MAN2B1 muta…
Haploinsufficiency of ARFGEF1 is associated with developmental delay, intellectual disability, and epilepsy with variable expressivity
2021
PURPOSE: ADP ribosylation factor guanine nucleotide exchange factors (ARFGEFs) are a family of proteins implicated in cellular trafficking between the Golgi apparatus and the plasma membrane through vesicle formation. Among them is ARFGEF1/BIG1, a protein involved in axon elongation, neurite development, and polarization processes. ARFGEF1 has been previously suggested as a candidate gene for different types of epilepsies, although its implication in human disease has not been well characterized.METHODS: International data sharing, in silico predictions, and in vitro assays with minigene study, western blot analyses, and RNA sequencing.RESULTS: We identified 13 individuals with heterozygous…
Genotype-first in a cohort of 95 fetuses with multiple congenital abnormalities: when exome sequencing reveals unexpected fetal phenotype-genotype co…
2020
PurposeMolecular diagnosis based on singleton exome sequencing (sES) is particularly challenging in fetuses with multiple congenital abnormalities (MCA). Indeed, some studies reveal a diagnostic yield of about 20%, far lower than in live birth individuals showing developmental abnormalities (30%), suggesting that standard analyses, based on the correlation between clinical hallmarks described in postnatal syndromic presentations and genotype, may underestimate the impact of the genetic variants identified in fetal analyses.MethodsWe performed sES in 95 fetuses with MCA. Blind to phenotype, we applied a genotype-first approach consisting of combined analyses based on variants annotation and …
NEXMIF encephalopathy: an X-linked disorder with male and female phenotypic patterns
2021
Contains fulltext : 231688.pdf (Publisher’s version ) (Closed access) PURPOSE: Pathogenic variants in the X-linked gene NEXMIF (previously KIAA2022) are associated with intellectual disability (ID), autism spectrum disorder, and epilepsy. We aimed to delineate the female and male phenotypic spectrum of NEXMIF encephalopathy. METHODS: Through an international collaboration, we analyzed the phenotypes and genotypes of 87 patients with NEXMIF encephalopathy. RESULTS: Sixty-three females and 24 males (46 new patients) with NEXMIF encephalopathy were studied, with 30 novel variants. Phenotypic features included developmental delay/ID in 86/87 (99%), seizures in 71/86 (83%) and multiple comorbidi…
De novo loss-of-function KCNMA1 variants are associated with a new multiple malformation syndrome and a broad spectrum of developmental and neurologi…
2019
Abstract KCNMA1 encodes the large-conductance Ca2+- and voltage-activated K+ (BK) potassium channel α-subunit, and pathogenic gain-of-function variants in this gene have been associated with a dominant form of generalized epilepsy and paroxysmal dyskinesia. Here, we genetically and functionally characterize eight novel loss-of-function (LoF) variants of KCNMA1. Genome or exome sequencing and the participation in the international Matchmaker Exchange effort allowed for the identification of novel KCNMA1 variants. Patch clamping was used to assess functionality of mutant BK channels. The KCNMA1 variants p.(Ser351Tyr), p.(Gly356Arg), p.(Gly375Arg), p.(Asn449fs) and p.(Ile663Val) abolished the …
Widening of the genetic and clinical spectrum of Lamb-Shaffer syndrome, a neurodevelopmental disorder due to SOX5 haploinsufficiency
2020
International audience; PURPOSE: Lamb-Shaffer syndrome (LAMSHF) is a neurodevelopmental disorder described in just over two dozen patients with heterozygous genetic alterations involving SOX5, a gene encoding a transcription factor regulating cell fate and differentiation in neurogenesis and other discrete developmental processes. The genetic alterations described so far are mainly microdeletions. The present study was aimed at increasing our understanding of LAMSHF, its clinical and genetic spectrum, and the pathophysiological mechanisms involved.METHODS: Clinical and genetic data were collected through GeneMatcher and clinical or genetic networks for 41 novel patients harboring various ty…
Interest of exome sequencing trio-like strategy based on pooled parental DNA for diagnosis and translational research in rare diseases.
2021
Abstract Background Exome sequencing (ES) has become the most powerful and cost‐effective molecular tool for deciphering rare diseases with a diagnostic yield approaching 30%–40% in solo‐ES and 50% in trio‐ES. We applied an innovative parental DNA pooling method to reduce the parental sequencing cost while maintaining the diagnostic yield of trio‐ES. Methods We pooled six (Agilent‐CRE‐v2–100X) or five parental DNA (TWIST‐HCE–70X) aiming to detect allelic balance around 8–10% for heterozygous status. The strategies were applied as second‐tier (74 individuals after negative solo‐ES) and first‐tier approaches (324 individuals without previous ES). Results The allelic balance of parental‐pool v…
DLG4-related synaptopathy: a new rare brain disorder
2021
Contains fulltext : 245031.pdf (Publisher’s version ) (Closed access) PURPOSE: Postsynaptic density protein-95 (PSD-95), encoded by DLG4, regulates excitatory synaptic function in the brain. Here we present the clinical and genetic features of 53 patients (42 previously unpublished) with DLG4 variants. METHODS: The clinical and genetic information were collected through GeneMatcher collaboration. All the individuals were investigated by local clinicians and the gene variants were identified by clinical exome/genome sequencing. RESULTS: The clinical picture was predominated by early onset global developmental delay, intellectual disability, autism spectrum disorder, and attention deficit-hyp…
Reducing diagnostic turnaround times of exome sequencing for families requiring timely diagnoses
2017
IF 2.137; International audience; BACKGROUND AND OBJECTIVE:Whole-exome sequencing (WES) has now entered medical practice with powerful applications in the diagnosis of rare Mendelian disorders. Although the usefulness and cost-effectiveness of WES have been widely demonstrated, it is essential to reduce the diagnostic turnaround time to make WES a first-line procedure. Since 2011, the automation of laboratory procedures and advances in sequencing chemistry have made it possible to carry out diagnostic whole genome sequencing from the blood sample to molecular diagnosis of suspected genetic disorders within 50 h. Taking advantage of these advances, the main objective of the study was to impr…
Missense variants in TAF1 and developmental phenotypes: Challenges of determining pathogenicity
2019
We recently described a new neurodevelopmental syndrome (TAF1/MRXS33 intellectual disability syndrome) (MIM# 300966) caused by pathogenic variants involving the X-linked gene TAF1, which participates in RNA polymerase II transcription. The initial study reported eleven families, and the syndrome was defined as presenting early in life with hypotonia, facial dysmorphia, and developmental delay that evolved into intellectual disability (ID) and/or autism spectrum disorder (ASD). We have now identified an additional 27 families through a genotype-first approach. Familial segregation analysis, clinical phenotyping, and bioinformatics were capitalized on to assess potential variant pathogenicity…