Long bundles of neurons that connect key regions in the brain develop abnormally in the first year of life in children with autism, according to new findings presented Friday at the International Meeting for Autism Research in San Diego.

A new analysis of children with autism and their unaffected parents provides the best evidence to date that mutations in multiple genes may work together to cause autism and related disorders.

Children with autism who have older siblings score lower on tests that assess their understanding of the thoughts, feelings and intentions of others, compared with those who don’t have older siblings.

Variants of three genes involved in a metabolic pathway together raise the risk of autism, according to a study published 5 March in the Journal of Neurodevelopmental Disorders.

Large studies on the epidemiology and genetics of epilepsy and autism have uncovered commonalities between the two disorders. But scientists are only beginning to untangle the biological roots of the overlap.

People who have severe gastrointestinal problems during childhood are no more likely to be on the autism spectrum than are healthy controls, a study reported 21 March in Developmental Medicine and Child Neurology.

The first comprehensive autism study in South Korea has found that the prevalence of the disorder is more than double the number in the United States.

The brain collects information on an object’s orientation, direction and speed all at the same time, according to a study published 15 April in NeuroImage.

Smaller-than-normal volume in several brain regions, including a region involved in relaying motor signals, could be a marker for repetitive behavior in 3-year-old children, according to a study published 7 April in Autism Research.

Good mouse models of autism, and accurate tests to assay their phenotypes, are key to both narrowing down a cause and developing effective treatments, argues expert Jacqueline Crawley.