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Mutations in Sex-Linked Genes Appear to Drive More Male Cases of Autism

ByTim De ChantNOVA NextNOVA Next

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One of autism’s enduring mysteries is that it seems to affect the sexes differently—boys are several times more likely to be diagnosed with the disorder than girls. Now, a new study suggests that small mutations in genes linked to sex differences may be helping drive that difference.

The study corralled genetic data from over 23,000 people, including over 8,600 people diagnosed with autism spectrum disorder and 15,000 people not diagnosed. The research team then went looking for single nucleotide polymorphisms, known as SNPs, which are one-letter changes to various genes.

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Sex-linked genes were associated with autism spectrum disorder.

In this case, Lauren Weiss, associate professor of psychiatry at the University of California, San Francisco, and her team sought out SNPs in sex-linked genes, including those that control for height, weight, and hip and waist measurements.

Researchers found a number of different mutations on these genes that they say “contribute disproportionately” to the association with autism spectrum disorder. “The same mechanisms acting on secondary sex characteristic differences later in life may influence ASD risk in early development,” they write .

Here’s Ann Griswold, reporting for Spectrum:

The fact that some of these SNPs also shape physical traits in a sex-specific way is particularly interesting, says Meng-Chuan Lai, assistant professor in psychiatry at the University of Toronto, who was not involved in the study. Scientists should examine whether sex differences in brain structure in people with autism track with the sex-specific SNPs, he says.

None of the SNPs have been previously associated with autism, suggesting that genetic databases may contain even more clues as to what predisposes a person to autism.