Genetics not environment biggest autism risk factor

The origins of Autism Spectrum Disorder have been the source of debate for decades, but a new study has found genes account for about 80 per cent of a child’s risk of developing the disorder.

Let's Go Shopping app for children with autism. Generic photos of the application. Founder Candice Taylor supplied.

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A new study has found genes account for about 80 per cent of a child’s risk of developing Autism Spectrum Disorder.

Published in JAMA Psychiatry today, the study, which is the largest of its kind, looked at data involving more than two million children born in Denmark, Finland, Sweden, Israel and Western Australia between 1998 and 2012.

All were tracked until 16 years of age and about 22,000 develop an autism spectrum disorder.

Researchers analysed potential ASD risk factors like genetics, environments and maternal effects and found inherited genes accounted for about 80 per cent of the risk of autism in children with the disorder.

The remainder of the risk was tied to as-yet-unidentified environmental causes.

Only about 1%, was due to maternal factors, researchers said, which may ease fears among parents that autism is caused by vaccinations, or factors such as a mother’s nutrient intake, or how a baby is delivered.

The results have paved the way for new research into the genetic causes of autism, which affects about 1 in 70 people in Australia.

The research team, led by Sven Sandin at the Karolinska Institute in Stockholm, Sweden, wrote in an editorial comment on the study that genetic factors were frequently ignored, and instead environmental factors “often receive disproportionate attention from the public and the media, even when (as in the case of vaccine fears), they are debunked”.

“The importance of this finding lies in the insight it provides for understanding the risk factors associated with ASD,” the researchers wrote.