Autism and Genome-Wide Association Studies

utism is one of the “most genetic ” psychiatric diseases. Its high heritability points towards a possible near complete genetic pathogenesis. However, despite enormous efforts during last years, that sometimes were even criticized the understanding of the disease causes and progress is still missing. A The first study looking at the genome level for genetic factors of autism in 99 affected families identified a region on chromosome 7q already in 1998 (1998). The results from the International molecular genetic study of the autism consortium were confirmed in the next year by French investigators (Philippe et al 1999). However, this study also found other 10 associated regions spread though the genome. Interestingly, one of the regions was localized at the chromosome Xp. The X chromosome associations could explain the gender difference in autism prevalence. But find-ings of parental inheritance of autism in some families argue against the association with gonosomal regions. Other mechanisms probably related to the effect steroid hormones on brain development might be responsible for the gen-der-related skewness of autism prevalence. A genome-wide association study targeted at the Asperger syndrome revealed some overlap loci between this en-tity and autism (3p14-24), but more interestingly an overlap between Asperger syndrome, autism and schizophrenia (1q21-22) (Ylisaukko-oja et al 2004). Further loci were found to be associated with autism on the chromosomes 12q14, 16p, 17q11.2 and 19p13 without identifying specific genes or variants (Philippi et al 2005; McCauley et a