The Genetics of Autism

Summary

Autism is a severe psychiatric disorder characterised by deficits in social interaction, disturbed communicationand adherence to stereotype routines and interests. Nowadays it is completely clear that this disorder has a biologicalbasis and many observations show strong genetic determination of autism. The importance of genetic factors issupported by frequent association of this disorder with known hereditary diseases or with various chromosomalaberrations, by high concordance of the disorder inmonozygotic twins, higher risk for the siblings of autistic patientsand also by the frequent occurrence of milder symptoms of the autistic spectrum in more distant relatives. All thesefindings show that the autistic phenotype results fromunfavourable combination of alleles of several genes in interplaywith factors of the environment. This model of multifactorial inheritance of autism serves at present as the startingpoint for the search for predisposing genes in the human genome. The association is tested between autism andalleles of candidate genes selected based on known biochemical and physiological role of their protein products, orbased on their location close to recurrent chromosomal rearrangements or in regions identified by whole-genomelinkage analyses. Studies of most of these genes have not yielded clear-cut results yet, but the participation of someof them in the aetiology of autism is possible.

Key words:
autism, multifactorial inheritance, candidate genes, association studies.