Common gene variants account for most genetic risk for autism

(NIH/National Institute of Mental Health) Most of the genetic risk for autism comes from versions of genes that are common in the population rather than from rare variants or spontaneous glitches. Heritability also outweighed other risk factors in this largest study of its kind to date. About 52 percent of the risk for autism was traced to common and rare inherited variation, with spontaneous mutations contributing a modest 2.6 percent of the total risk.