Search results for "INTELLECTUAL DISABILITY"

X-LINKED INTELLECTUAL DISABILITY

2013

The intellectual disability is found in approximately 2-3% of the population in a mild-to-moderate form and 0.5-1% in a moderate-to-severe form. The mutations on the chromosome X are responsible for both syndromic and non-syndromic intellectual disability. In the syndromic forms behavioral disorders, autism and/or seizures are frequent.

A rare unbalanced translocation 1;18 in a child with epilepsy, mild dysmorphology and mental retardation

2012

Selection and evaluation of Internet information by adults with intellectual disabilities

2018

Internet offers people with intellectual disabilities (ID) unique opportunities to access information and to participate in society. But concerns have been raised about the potential risks they face when accessing the Internet (e.g. giving credit to false information, being exposed to manipulative content). As part of the current debate between positive risk-taking and overprotection, our study empirically tested the extent to which 43 adults with ID identified and selected topically relevant as well as trustworthy web pages while searching the Internet for several topics (e.g. Can social networks use your pictures for advertisement?). Participants also justified their search decisions. Res…

New Insights into Potocki-Shaffer Syndrome: Report of Two Novel Cases and Literature Review

2020

Potocki-Shaffer syndrome (PSS) is a rare non-recurrent contiguous gene deletion syndrome involving chromosome 11p11.2. Current literature implies a minimal region with haploinsufficiency of three genes, ALX4 (parietal foramina), EXT2 (multiple exostoses), and PHF21A (craniofacial anomalies, and intellectual disability). The rest of the PSS phenotype is still not associated with a specific gene. We report a systematic review of the literature and included two novel cases. Because deletions are highly variable in size, we defined three groups of patients considering the PSS-genes involved. We found 23 full PSS cases (ALX4, EXT2, and PHF21A), 14 cases with EXT2-ALX4, and three with PHF21A only…

De novo GRIN2A variants associated with epilepsy and autism and literature review

2021

N-methyl-D-aspartate receptors (NMDAR) are di- or tri-heterotetrameric ligand-gated ion channels composed of two obligate glycine-binding GluN1 subunits and two glutamate-binding GluN2 or GluN3 subunits, encoded by GRIN1, GRIN2A–D, and GRIN3A–B receptor genes respectively. Each NMDA receptor subtype has different temporal and spatial expression patterns in the brain and varies in the cell types and subcellular localization resulting in different functions. They play a crucial role in mediating the excitatory neurotransmission, but are also involved in neuronal development and synaptic plasticity, essential for learning, memory, and high cognitive functions. Among genes coding NMDAR subunits…

Disruption of the ATXN1-CIC complex causes a spectrum of neurobehavioral phenotypes in mice and humans

2017

International audience; Gain-of-function mutations in some genes underlie neurodegenerative conditions, whereas loss-of-function mutations in the same genes have distinct phenotypes. This appears to be the case with the protein ataxin 1 (ATXN1), which forms a transcriptional repressor complex with capicua (CIC). Gain of function of the complex leads to neurodegeneration, but ATXN1-CIC is also essential for survival. We set out to understand the functions of the ATXN1-CIC complex in the developing forebrain and found that losing this complex results in hyperactivity, impaired learning and memory, and abnormal maturation and maintenance of upper-layer cortical neurons. We also found that CIC …

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…

High Rate of Recurrent De Novo Mutations in Developmental and Epileptic Encephalopathies

2017

Item does not contain fulltext Developmental and epileptic encephalopathy (DEE) is a group of conditions characterized by the co-occurrence of epilepsy and intellectual disability (ID), typically with developmental plateauing or regression associated with frequent epileptiform activity. The cause of DEE remains unknown in the majority of cases. We performed whole-genome sequencing (WGS) in 197 individuals with unexplained DEE and pharmaco-resistant seizures and in their unaffected parents. We focused our attention on de novo mutations (DNMs) and identified candidate genes containing such variants. We sought to identify additional subjects with DNMs in these genes by performing targeted sequ…

Heterozygous HMGB1 loss-of-function variants are associated with developmental delay and microcephaly

2021

International audience; 13q12.3 microdeletion syndrome is a rare cause of syndromic intellectual disability. Identification and genetic characterization of patients with 13q12.3 microdeletion syndrome continues to expand the phenotypic spectrum associated with it. Previous studies identified four genes within the approximately 300 Kb minimal critical region including two candidate protein coding genes: KATNAL1 and HMGB1. To date, no patients carrying a sequence-level variant or a single gene deletion in HMGB1 or KATNAL1 have been described. Here we report six patients with loss-of-function variants involving HMGB1 and who had phenotypic features similar to the previously described 13q12.3 m…

A novel mutation of WDR62 gene associated with severe phenotype including infantile spasm, microcephaly, and intellectual disability

2017

Abstract The autosomal recessive form of primary microcephaly (MCPH) is a rare disorder characterized by head circumference of at least 3 standard deviation below the mean. The MCPH exhibits genetic heterogeneity with thirteen loci (MCPH1-MCPH13) identified, and associated with variable degree of intellectual disability. It has been reported that WDR62 is the second causative gene of autosomal recessive microcephaly (MCPH2) playing a significant role in spindle formation and the proliferation of neuronal progenitor cells. We report a clinical feature, electroclinical findings, and clinical course of a patient with a severe phenotype of MCPH2 including microcephaly, refractory infantile spas…