Three new studies appear to reinforce the idea that autism is connected to genetic mutations, at least in a subset of patients with the condition. It's a big story that a number of news agencies picked up, with Voice of America and Forbes magazine among those offering the more interesting summaries. Nature published each of the research efforts and discusses the findings in a separate news article.
Each of the studies involved extensive exome sequencing, among the largest yet for autism. And as Nature explains, the studies collectively gave "strong evidence" for the existence of three new autism genes, known as CHD8, KATNAL2 and SCN2A, backing the notion that many genes increase a risk for autism. The scientists, Nature notes, found evidence that there could be up to 1,000 high-risk autism genes.
But Voice of America and Forbes, among others, zeroed in on some of more detailed findings. As Voice of America points out, the studies revolved around DNA mutations in a small group of autistic children that didn't appear to be inherited, but their presence heightens the autism risk. One concluded that a child's chance of developing autism spectrum disorders such as Asperger's syndrome or repetitive behaviors jumps 5 to 20 times if mutations in the exome portion of the gene are there, according to both news agencies. Another study supported an earlier effort concluding that telltale gene mutations have a much greater chance of appearing in male DNA than in female DNA, and that middle-aged and older men who father children boost those gene mutation risks.
In Voice of America, we hear from Mark Daly from the Center for Human Genetics at the Broad Institute at Harvard University and the Massachusetts Institute of Technology, who led one of the studies. He explained that more than 50% of autism cases don't have the mutations on which the three new studies focused, but said "because they are very rare, they allow us to pinpoint when we see multiple kids with autism with mutations in the same gene."
Interesting findings, all, as clinical and preclinical autism studies continue.