The question of what causes autism spectrum disorder (ASD) is one that has boggled the medical community for some time now. But researchers may have made a breakthrough discovery in a recent, "unprecedentedly large" study.
According to an article in the CBC, American and Swedish researchers claim that autism isn't caused by environmental factors or mutations in DNA, but "common variants" that exist in everyone.
"Although each exerts just a tiny effect individually, these common variations in the genetic code add up to substantial impact, taken together," said Joseph Buxbaum, a co-author of the study and a professor of medicine at Mount Sinai medical school in New York City.
Published in the journal Nature Genetics, the study analyzed the data over 400 Swedes with ASD born between 1982 and 2007, and 2,580 as part of the control group.
Almost half of a person's susceptibility for inheriting autism comes from genetic variations.
"The family may have common variation that puts it at risk, but if there is also a de novo [spontaneous] mutation on top of that, it could push an individual over the edge."
So it seems inherited risk for autism outweighs that which arises from rare mutations in genes such as CHD8.
Printer-friendly version