The genetics of autism

Objective: To review systematically the empirical evidence for the involvem ent of genetic risk factors in infantile autism. Method: We aimed at including all relevant papers written in English. We co nducted a Medline search in September 2000. In addition we searched the ref erence lists of related papers. Results: A relatively small number of reports including family and twin stu dies, comorbidity, cytogenetic and molecular genetic studies were reviewed. Conclusion: As well family, twin, cytogenetic and molecular genetic studies supported the importance of genetic risk factors in infantile autism. In m ost individual cases probably at least a few gene variants simultaneously d etermine the genetic risk. Presently the most interesting chromosome region s concerning the aetiology of autism are chromosomes 7q31-35, 15q11-13 and 16p13.3 which have been suggested by different lines of genetic research.