Small differences in as many as a thousand genes contribute to risk for autism, according to a study published in the journalNature. The study examined data on several types of rare, genetic differences in more than 14,000 DNA samples from parents, affected children, and unrelated individuals to dramatically expand the list of genes identified with autism spectrum disorder (ASD).
Most of the genes that contribute to autism remain unknown, but the current study increases the number of definitive autism genes almost fourfold to 33, compared to the nine genes most closely tied to risk in recent years by similar studies in several labs. It also identified more than 70 additional likely ASD genes. Each of these genes is mutated in more than five percent of individuals with autism, signifying a large relative contribution to risk for a complex genetic disease.
By casting a wider net, a research team from 37 institutions found that previously unsuspected sets of genes may be involved in ASD risk, including some that control how nerve networks form in the brain. Occurring in one out of 68 children in the United States, ASD affects a person’s social interactions, including communication, as well as behaviors with varying levels of severity.
For the first time, the study authors were able to assess the effects of both inherited genetic differences and those that happen spontaneously in the sperm and eggs that go on to form human embryos. While small, rare genetic differences in the top 107 genes were found to confer a relatively large jump in a person’s risk, many more changes in other genes add smaller amounts of risk. According to the authors, the interplay between gene variations, both common and rare, holds the key to understanding autism. Learn more.
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