The loss of 21 genes on chromosome 3 may substantially raise the risk of autism.

Researchers have engineered two generations of monkeys with mutations in SHANK3, a top autism gene. The first generation shows traits reminiscent of the condition.

About half of boys and men with fragile X syndrome injure themselves — and continue to do so for years.

Mice colonized with gut microbes from some autistic boys show behaviors like those of the boys.

Restricted and repetitive behaviors decrease significantly in about 75 percent of autistic children from age 3 to 11.

Autistic infants who have extreme responses to sights, sounds or textures tend to harm themselves as toddlers.

Boys and girls with autism get virtually identical scores on three commonly used diagnostic tests, suggesting that sex doesn’t affect the scores.