Approach to the genetic evaluation of the child with autism.

Autism is a heterogeneous entity that clearly has a substantial genetic component to its cause. There is likely enough evidence to suggest that there are common genetic mechanisms that predispose to various psychiatric disorders. More recent studies have attempted to identify the specific genes involved in predisposition to autism. In general, such conditions can be subdivided into metabolic, mitochondrial, chromosomal, and monogenic (ie, caused by mutation in a single gene). This article examines what conditions should be considered in the child who does not appear to have a syndromic cause as the reason for the autistic phenotype.