Autism, mental retardation, and chromosomal abnormalities

Abstract

There are reports of sex chromosomal abnormalities including XXY, XYY, and fragile X karyotypes in autistic individuals, but structural autosomal defects have rarely been reported. This paper presents four patients with autism, mental retardation, minor dysmorphic features, and structural autosomal defects. These patients shared autistic features including fascination with inanimate objects, catastrophic reactions to changes in their environment or their daily routine, echolalia, and poor relatedness; IQ scores indicate mild to severe retardation. Their autosomal abnormalities included inversion/duplications of 3p and 16q, 5p+, and 17p-. Parental chromosomes were all normal. Chromosomal analysis should be performed on mentally retarded, autistic individuals, especially those with minor physical anomalies and no specific etiology for their retardation.

The neuroligin and neurexin families: from structure to function at the synapse

“…Considering the potential role of neuroligins in dictating the E/I ratio, aberrations in the expression of these proteins may be associated with these disorders. Consistent with this, rearrangement of chromosomal regions harboring neuroligin genes have been linked to autism [137][138][139][140][141][142][143]. Other investigations have revealed that mutations in neuroligin 3 and neuroligin 4 are associated with autism [78,[143][144][145].…”

Specific Genetic Disorders and Autism: Clinical Contribution Towards their Identification

“…Autism was reported in at least four patients exhibiting the Smith-Magenis deletion (Cabral de Almeida, Reis, & Martins, 1989;Lockwood et al, 1988;Mariner et al, 1986;Vostanis, Harrington, Prendergast, & Farndon, 1994). To date, it is not possible to estimate the absolute or relative prevalence of the syndrome within autism.…”

Cell Adhesion Molecules in Synapse Formation: Figure 1.

“…All presently identified neuroligin-3 and -4 mutations result in a loss of function, either attributable to truncation or a point mutation of the cholinesterase domain, which result in intracellular retention (Chih et al, 2004;Comoletti et al, 2004). Furthermore, it appears that point mutations and chromosomal rearrangements in regions of the genome containing the genes for neuroligin-2 and PSD-95 are associated with autism (Mariner et al, 1986;Risch et al, 1999).…”