The pupils of children with autism contract more slowly in response to flashes of light than those of their healthy peers, according to findings published in the November issue of the Journal of Autism and Developmental Disorders.

Using new genetic screening technology, a few research groups are finding that a surprisingly large number of children with autism — at least five percent — have an underlying problem with their mitochondria, the energy factories of the cell.

There are clinical, anatomical and genetic overlaps between autism and certain rare developmental disorders of the cerebellum, and these disorders may help scientists understand autism, according to several studies published in the past year.

Studies on younger siblings of children with autism are finding that during tests of sensory or perceptual processing, these baby sibs show abnormally fast brain responses, rather than a delay.

Autism may be the result of faulty wiring that occurs during early brain development, according to two independent studies that looked at the origins of circuit disruption.

Deletions or duplications of chromosomal segment 16p11.2 — previously reported as a key autism region — are seen in people with developmental delays and speech and behavioral problems, but not necessarily autism. That’s the finding from two large studies published last week of people carrying these rare genetic variations.

Deleting MeCP2, the gene that’s mutated in Rett syndrome, alters both the size and function of neurons in the mouse brain — at least in one brain region, the locus ceruleus — according to a 30 September report in the Journal of Neuroscience.

A report in the October issue of Nature Neuroscience says the amygdala — the brain region that controls emotions, as well as the way individuals interpret and respond to social situations and recognize possible threats — governs the preference for personal space.

Genetic analysis of one Belgian family with a history of autism has pinpointed a piece of DNA on chromosome 16, within a segment thought to be missing in about one percent of all cases of autism. The unpublished data was presented on Saturday at the World Congress of Psychiatric Genetics in San Diego.

The Psychiatric GWAS Consortium has released its first batch of analyses, identifying several significant common variations associated with schizophrenia. The results were presented Sunday at the World Congress of Psychiatric Genetics in San Diego.