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

People on the spectrum, and girls and women in particular, are at high risk of suicide; siblings of autistic people are also at heightened risk.

Families of children with mutations in a gene called SYNGAP1 have spurred research into the effects of the mutations on people — and how to treat them.

A website called GeneMatcher has helped researchers identify a new gene for intellectual disability, developmental delay and autism.

Children in families with a history of brain conditions may be at increased odds of being autistic.

Without timely intervention, intellectual disability in autistic children can worsen as they grow older.

Autism may be just as common among children missing a segment of chromosome 16 as it is in those with an extra copy.

Two independent sets of mice missing a copy of SETD5, a top autism gene, link the gene to the condition’s traits.