Genetics plays outsized role in autism, large study shows
Autism is more heritable than anorexia, alcohol dependence, depression and obsessive-compulsive disorder, according to an analysis of data from nearly 4.5 million people1.
At 64 percent, its heritability is similar to that of schizophrenia, attention deficit hyperactivity disorder (ADHD) and bipolar disorder, the new study shows.
Heritability refers to the degree to which differences in people’s genes, as opposed to environmental factors, account for their traits. The new study measures the heritability of these conditions by calculating how often pairs of siblings — who share about half their DNA — have the same diagnosis compared with half siblings, who have about one-quarter of their genes in common.
The estimate for autism is in line with results from twin studies. Those studies show that identical twins, who have nearly identical DNA, are more likely than fraternal twins to both have autism. (Fraternal twins share about half their DNA, as other siblings do.)