Carriers of fragile X premutations in Ricaurte, Colombia, have more medical problems than carriers living elsewhere — and discovering why might yield treatments for the syndrome.

Autism may be accompanied by high levels of the hormone leptin in early childhood.

Autism is predominantly genetic in origin, but a growing list of prenatal exposures for mother and baby may sway the odds.

Triggering an immune defense in newborn male mice missing a copy of TSC2, a gene linked to autism, impairs the mice’s social memory.

Autism results from an interplay between genetics and the environment, but it has been tough to nail down the environmental factors involved.

Fever in pregnant rats around the time of delivery disrupts their pups’ communication and social behavior.

Women whose children are severely autistic have lower serotonin levels than do those whose children have mild or moderate autism traits.

A remote Colombian town is home to the world’s largest cluster of people with fragile X syndrome. Scientists are learning from them — and trying to help.

Watch the complete replay of Janine LaSalle discussing gene-environment interactions and autism.

Depression is more than three times as common among adults with autism as it is in the general population.