Several brain regions in people with autism become enlarged earlier than usual during childhood and shrink too soon during adulthood, finds an eight-year imaging study.

People with autism who have mutations in a gene called PTEN have a distinct profile of cognitive impairments and structural abnormalities in the brain. The profile, published 7 October in Molecular Psychiatry, points to a subtype of autism with these features.

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.

Mice with mutations in the autism-linked gene WDFY3 have enlarged brains reminiscent of those seen in some children with autism, according to a study published 8 September in Nature Communications.

Deletion and duplication of the 16p11.2 chromosomal region have opposite effects on brain size, but produce similar alterations in the brain’s processing of sound. Researchers reported these and other unpublished findings at the 2013 Society for Neuroscience annual meeting in San Diego, painting a complex picture of the region’s role in autism.

Social difficulties and early overgrowth of the brain are trademarks of autism, yet a direct connection between the two has been elusive. One group of researchers may have found a link between the two symptoms and a way to treat both at once, they reported Sunday at the 2013 Society for Neuroscience annual meeting in San Diego.
 

Girls with autism tend to have smaller heads and bodies than their typically developing peers, whereas boys with the disorder tend to have average-sized heads and slightly larger bodies, report two studies published in July.

Two studies published 9 July bolster the hypothesis that immune molecules in a pregnant woman’s bloodstream may sometimes cause autism in her child.

Infants who go on to develop autism have excess fluid between the top of the brain and the skull that persists from about 6 months to 2 years of age, according to a study published 9 July in Brain.