Autism is more heritable than anorexia, alcohol dependence, depression and obsessive-compulsive disorder, according to an analysis of data from nearly 4.5 million people.
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.
[Tinca Polderman, assistant professor of complex trait genetics at VU University Amsterdam in the Netherlands] and her colleagues combed through Sweden’s Multi-Generation Register to identify siblings born in Sweden since 1932. For each sibling pair, they included the two eldest siblings in a family who were born within five years of each other. They looked at full siblings and half siblings who share a mother. The final sample includes 4,408,646 people.
The researchers identified people diagnosed with any of the eight psychiatric conditions. For autism, the study included people born since 1990, when diagnoses of the condition first appeared.
She and her colleagues are looking for common variants that can help explain the overlap in traits of autism, schizophrenia and ADHD seen in siblings. They are also using the data to predict a person’s odds of being diagnosed with one of the conditions.
Read full, original post: Genetics plays outsized role in autism, large study shows