Genetics of autism

Autism spectrum disorders (ASDs) are heterogeneous neurodevelopmental syndromes characterized by deficits in the core domains of social behavior, language, and the presence of restricted interests and activities. General intelligence and sensory-motor function are often affected, and other medical problems, including seizures, are variably observed. There is evidence for high heritability in autism, but the forms of the genetic mutations contributing to autism and ASD susceptibility are very heterogeneous. These causes include a number of rare genetic syndromes (fragile X, [dup]15q, tuberous sclerosis complex), each of which accounts for 1% to 2% of ASD in large studies. Recently, rare mutations in single genes and a significant number of new chromosomal structural variations have been identified, suggesting that rare mutations may be a significant cause of ASD. Here we discuss the progress in defining the genetic basis of ASD and the current state of genetic testing in practice, a field that is rapidly evolving.