Fragile X syndrome, the most common inherited cause of intellectual impairment and the most common single gene associated with autism, generally occurs for fragile X mental retardation 1 (FMR1) alleles that exceed 200 CGG repeats (full-mutation range).
A loss-of-function mutation in the FMR1 gene leads to subtle changes in neural development and subsequent mental impairment characteristic of FX. hNPCs were isolated from fetal cortex carrying the FMR1 mutation to determine whether aberrations occur in their proliferation and differentiation.
Fragile X Syndrome (FXS) is the main genetic cause of autism and intellectual deficiency resulting the absence of the Fragile X Mental Retardation Protein (FMRP).
By combining the clinical data of all patients with MEF2C point mutations published so far with the phenotype of our patient, a targeted search for MEF2C mutations could be applied to patients with a severe intellectual deficiency associated with absence of language and hypotonia, strabismus, and epilepsy (started after 6 months, often well controlled by valproate).
No clear association has been found between DNA mutations, protein expression, and IQ scores, although distal deletions in the dystrophin gene have been reported in association with intellectual impairment.
Dystrophin gene mutation positions were dichotomized into groups (upstream versus downstream of exon 43, location of isoforms previously linked to intellectual impairment).
Fragile X Syndrome (FXS) is the main genetic cause of autism and intellectual deficiency resulting the absence of the Fragile X Mental Retardation Protein (FMRP).
In humans, arginase I (AI)-deficiency results in hyperargininemia, a metabolic disorder with symptoms of progressive neurological and intellectual impairment, spasticity, persistent growth retardation, and episodic hyperammonemia.
Other potential genes responsible for intellectual deficiency disrupted as a result of patient's chromosomal rearrangement map at 12q14.1 (TAFA2), 12q23.1 (METAP2), and 11p14.1 (BDNF).
The effect of either ApoE epsilon4 allele and BDNF genetic variant on the neuropsychological pattern of mental impairment was examined both in terms of group differences in performance on the neuropsychological tests between carriers and non-carriers of each variant and by selecting the best predictor of cognitive performance among demographic and genetic factors by means of a multiple regression analysis.