People with autism may belong to one of four distinct categories based on their medical history, according to a study published in the October Autism Research.

The first genome-wide linkage analysis of more than 1,200 families has identified regions implicated in autism as originating from either the paternal or maternal copies of chromosomes.

Two new studies use medical records from countries with nationalized health care to link autoimmune disease and obesity in parents to the likelihood of having a child with autism.

Chemicals produced by their mother’s immune system in utero alter the size of several key brain regions in people with schizophrenia, enlarging chambers that store cerebrospinal fluids, and shrinking parts of the cortex involved in processing emotion and memory.

New DNA tests for fragile X syndrome are quick, but also raise ethical questions: they pick up abnormalities in some babies who won’t develop symptoms until adulthood, if at all.

A new wave of genetic tests for fragile X syndrome, the leading cause of inherited mental retardation and the most common genetic cause of autism, may make it possible to routinely screen pregnant women and newborns for the syndrome.

Research has hinted that the season of a child’s birth may play some role in his or her risk of developing various neuropsychiatric disorders. But it’s the season of conception that really matters, a new study suggests.

A study of postmortem tissue shows that microglia, cells that provide immune protection to the brain, are altered in the brains of individuals with autism.

A drug that interferes with a biochemical pathway important in cancer can reverse some brain defects in mouse models of fragile X syndrome, according to a study published 11 August in the Journal of Neuroscience.

In order to understand the interaction between genes and environment in autism, researchers in different disciplines will have to move back and forth between those two realms, stretching out of their intellectual comfort zones. But if the mood at an interdisciplinary workshop two weeks ago is any indication, that challenge is also a source of excitement.