The Genetics of Autism

Genetics may play a bigger part in autism than scientists had thought. One thing we know for sure, it's not vaccines or poor parenting. Scientists in London studied over 6,400 twin pairs in England and Wales and all had been raised by their parents in the same environment.

The incidence of identical twins having ASD, or autism spectrum disorder, was between 77 and 99 percent. That's much higher than non-identical twins, whose chances were between 22 and 65 percent.

For years we thought the environment played a larger role, but genes may figure more prominently. We haven't identified any one gene responsible for ASD but there are many being studied, such as EN2, a gene critical to midbrain and cerebellum development. Another is Reelin, a protein important in brain development that in adults is critical to learning and memory.

Scientists are looking at the role genes play in serotonin regulation since autistics consistently show elevated levels. Could this feel good hormone play a role? Another hormone system called the arginine-vasopressin may affect social behavior. One of its genes is now also a candidate for autism. FOXP2 is a causal gene for a severe speech and language disorder in a three-generation family. Because language impairments are a hallmark of autism, scientists are targeting this gene for a closer look. These are just a few of the many genes being studied.

As more people become aware of ASD and as more children are diagnosed, the pressure is building to further understand this disorder.