Genetics and Autism
The Genetics of Autism
Many researchers believe that autism may be a result of a combination of genetic and environmental factors. The identification of specific genes which may be responsible for the development of autism remains a major research focus with the objective of developing an understanding of the role genetics play in the underlying pathophysiology of the disorder.
The role of genetics in autism is supported by studies of monozygotic (identical) twins which have shown a concordance rate of 60 to 90% for autism. The incidence of autism in children who have an older sibling diagnosed with autism has also been shown to be 25 times higher than in the general population.
While researchers have identified a number of genes which may likely play a role in the development of autism, most genes which have been shown to be associated with autism are represented in less than 1% of individuals with autism spectrum disorders.
While autism is not typically the results of a single-gene mutation or a single chromosome abnormality, there are single gene disorders like Fragile X and Rett Syndrome which are associated with developmental delays in children.
Recent genetic studies have demonstrated that many individuals with autism have several copy number variations (CNV’s) or spontaneous duplications or deletions in specific locations on their DNA. These rearrangements of an individual’s genetic sequence is now thought to increase susceptibility to autism. This suggests that the majority of cases of autism are likely a result of variations to several genes which increase an individual’s predisposition to autism.
Learn about genetics
Suggested Reading:
Abrahams BS, Geschwind DH. Advances in autism genetics: on the threshold of a new neurobiology. Nat Rev Genet. 2008; 9: 341–355. (link)
El-Fishawy P, State MW. The genetics of autism: key issues, recent findings, and clinical implications the genetics of autism: key issues, recent findings, and clinical implications. Psychiatr Clin North Am. 2010; 33:83-105. (link)
Marchant GE, Robert JS. Genetic testing for autism predisposition: ethical, legal and social challenges. Hous. J. Health L. & Pol’y 2010; 9:203-35. (link)
Christine M. Freitag CM, Staal W, Klauck SM, Duketis E, Waltes R. Genetics of autistic disorders: review and clinical implications. Eur Child Adolesc Psychiatry 2010; 19:169–178. (link)
