Less than one-third of sibling pairs with autism who carry rare mutations in autism-linked genes share those mutations, according to the largest study yet to sequence whole genomes of people with the disorder. The study questions the assumption that autism’s risk factors run in families, but some experts are skeptical.

Having an enlarged head in early childhood is not a reliable marker of autism, according to two new studies that tracked changes in head and body size in children over time.

People with autism tend to carry mutations that duplicate or delete several genes at once, according to a large study published 1 May in the American Journal of Human Genetics.

Children of women who have attention deficit hyperactivity disorder are at increased risk for autism and attention deficit, according to a study published 21 January in the Journal of Child Psychology and Psychiatry. This suggests the two diseases have common risk factors.

In families with a history of autism, the affected children are seven times more likely to also have epilepsy than their unaffected siblings, according to a study published 1 December in Molecular Autism. The results suggest that epilepsy and autism share some risk factors.

Variants in a language gene linked to autism are only modestly associated with the disorder in a large sample, according to a study published 17 October in PLoS One.

Children who have older siblings with autism are seven times more likely than those in the general population to receive autism diagnoses themselves, according to a large Danish study published 19 August in JAMA Pediatrics.

Researchers can increase the power of studies that link genetic variants to autism by factoring in potential subgroups of the disorder, according to a report published 26 June in PLoS One.
 

A 36-question survey detects features of autism in as much as 23 percent of parents of children with autism and 9 percent of control parents, researchers reported 20 February in Autism Research.

Members of families that have multiple children with autism have more features of the disorder than do those from families that have only one child with autism, according to a study published 2 November in the Journal of Autism and Developmental Disorders.