Search results for " Mental retardation"

Attribution style in adolescents with Down’s sindrome

2005

Educational research places emphasis on the fact that individuals who have experienced repeated failures may develop an attribution profile characterized by a bias towards primarily external causes. The aim of this study is to compare the attribution style of adolescents with Down's syndrome with that of normal children and adolescents matched for mental and chronological age; three groups consisting of 10 participants each were employed, an experimental group and two control groups were employed. The experimental group were Down's syndrome adolescents. Participants in the first control group were matched to the experimental groups for mental age, and those in the second for chronological a…

The development of children's perception of hierarchical patterns : an investigation across tasks and populations

2011

The thesis investigated the development of children’s global/local processing hierarchical patterns introduced by Navon (1977). The objectives were to understand more comprehensively the developmental characteristics of children’s perception through their global and local processing of hierarchical patterns, by considering the effects of age, stimuli properties, duration of exposure to the stimuli and gender in a perceptual task and a drawing task. These effects were tested in 3 different populations: typically developing children, children with mental retardation and early blind children. The results revealed that typically developing children attended to both the local and global level of…

Intragenic FMR1 disease-causing variants: a significant mutational mechanism leading to Fragile-X syndrome

2017

International audience; Fragile-X syndrome (FXS) is a frequent genetic form of intellectual disability (ID). The main recurrent mutagenic mechanism causing FXS is the expansion of a CGG repeat sequence in the 5'-UTR of the FMR1 gene, therefore, routinely tested in ID patients. We report here three FMR1 intragenic pathogenic variants not affecting this sequence, identified using high-throughput sequencing (HTS): a previously reported hemizygous deletion encompassing the last exon of FMR1, too small to be detected by array-CGH and inducing decreased expression of a truncated form of FMRP protein, in three brothers with ID (family 1) and two splice variants in boys with sporadic ID: a de novo …

Association of a functional deficit of the BKCa channel, a synaptic regulator of neuronal excitability, with autism and mental retardation

2006

International audience; Objective: Autism is a complex, largely genetic psychiatric disorder. In the majority of cases, the cause of autism is not known, but there is strong evidence for a genetic etiology. To identify candidate genes, the physical mapping of balanced chromosomal aberrations is a powerful strategy, since several genes have been characterized in numerous disorders. In this study, the authors analyzed a balanced reciprocal translocation arising de novo in a subject with autism and mental retardation. Method: The authors performed the physical mapping of the balanced 9q23/ 10q22 translocation by fluorescent in situ hybridization experiments using bacterial artificial chromosom…

Recurrent missense variant in the nuclear export signal of FMR1 associated with FXS-like phenotype including intellectual disability, ASD, facial abn…

2021

Fragile X syndrome (FXS; MIM 300624) is an X-linked genetic disorder characterized by physical abnormalities associated with intellectual disability and a wide spectrum of neurological and psychiatric impairments. FXS occurs more frequently in males, 1 in 5000 males and 1 in 8000 females accounting for 1-2% of overall intellectual disability (ID). In more than 99% of patients, FXS results from expansions of a CGG triplet repeat (>200 in male) of the FMR1 gene. In the last years an increasing number, albeit still limited, of FXS subjects carrying FMR1 mutations including deletions, splicing errors, missense, and nonsense variants was reported. Nevertheless, the studies concerning the func…

Array-CGH defined chromosome 1p duplication in a patient with autism spectrum disorder, mild mental deficiency, and minor dysmorphic features

2010

Polysomnographic Findings in Fragile X Syndrome Children with EEG Abnormalities

2019

Fragile X syndrome (FXS) is a genetic syndrome with intellectual disability due to the loss of expression of the FMR1 gene located on chromosome X (Xq27.3). This mutation can suppress the fragile X mental retardation protein (FMRP) with an impact on synaptic functioning and neuronal plasticity. Among associated sign and symptoms of this genetic condition, sleep disturbances have been already described, but few polysomnographic reports in pediatric age have been reported. This multicenter case-control study is aimed at assessing the sleep macrostructure and at analyzing the presence of EEG abnormalities in a cohort of FXS children. We enrolled children with FXS and, as controls, children wit…

Xq27 FRAXA Locus is a Strong Candidate for Dyslexia: Evidence from a Genome-Wide Scan in French Families

2012

Dyslexia is a frequent neurodevelopmental learning disorder. To date, nine susceptibility loci have been identified, one of them being DYX9, located in Xq27. We performed the first French SNP linkage study followed by candidate gene investigation in dyslexia by studying 12 multiplex families (58 subjects) with at least two children affected, according to categorical restrictive criteria for phenotype definition. Significant results emerged on Xq27.3 within DYX9. The maximum multipoint LOD score reached 3,884 between rs12558359 and rs454992. Within this region, seven candidate genes were investigated for mutations in exonic sequences (CXORF1, CXORF51, SLITRK2, FMR1, FMR2, ASFMR1, FMR1NB), al…

The angelman syndrome: A brief review

2017

Angelman's Syndrome (AS) was described for the first time by Harry Angelman in the 1960s, based on obervation of three child patients with similar physical and behavioral features such as severe intellectual impairment, lack of language, motor disorders and happy behaviour. Many years later the typical patients' features were identified as linked to genetic abnormalities mainly characterized by neurological symptoms. Life expectancy is good although the symptoms tend to be stable and severe.

Ythdf is a N6‐methyladenosine reader that modulates Fmr1 target mRNA selection and restricts axonal growth in Drosophila

2021

Abstract N6‐methyladenosine (m6A) regulates a variety of physiological processes through modulation of RNA metabolism. This modification is particularly enriched in the nervous system of several species, and its dysregulation has been associated with neurodevelopmental defects and neural dysfunctions. In Drosophila, loss of m6A alters fly behavior, albeit the underlying molecular mechanism and the role of m6A during nervous system development have remained elusive. Here we find that impairment of the m6A pathway leads to axonal overgrowth and misguidance at larval neuromuscular junctions as well as in the adult mushroom bodies. We identify Ythdf as the main m6A reader in the nervous system,…