Most studies define high-functioning children as those with an IQ above 70 or 80, but this is problematic for a number of reasons, say some scientists. The assumption underlying the use of high IQ as a synonym for high functioning is suspect because social and communicative abilities may have a far greater impact on an individual’s daily interactions.

Spontaneous mutations that change a single DNA base account for a large proportion of cases of unexplained mental retardation, according to a study published in the December Nature Genetics.

Two independent groups have created mice that have deletions or duplications in a large section of chromosome 16. Each team has produced an animal with a different set of features, some of which — such as large head size and repetitive behaviors — are reminiscent of people with autism.

Individuals with a deletion in the 16p11.2 chromosomal region — which has been linked to autism in several studies — show features of autism spectrum disorders including language delay, according to a study published in October.

Deletion of the chromosomal region 17q12 dramatically increases the risk for autism and schizophrenia, according to a large study published last week in the American Journal of Human Genetics. Individuals missing this sizeable region are about 14 times more likely to develop one of those disorders, the study reports.

Ricardo Dolmetsch is making neurons from induced pluripotent stem cells derived from people with Timothy syndrome, a rare single-gene disorder that causes heart arrhythmias and autism. On Wednesday morning at the Society for Neuroscience annual meeting in San Diego, Dolmetsch talked to SFARI about how this approach could help autism research.

Three themes — heterogeneity, phenotype, and trajectory — are beginning to emerge in diverse lines of inquiry into autism, according to speakers at a satellite symposium of the Society for Neuroscience annual meeting in San Diego.

Researchers have narrowed down a genetic region associated with autism to one protein, cadherin 8, that helps bind cells together, according to a study published online in October in the Journal of Medical Genetics. This is the first time CDH8, the gene that encodes this protein, has been associated with autism.

Loss of activity of FOXP1, a member of a family of genes that regulate gene expression, leads to general behavioral defects, including delays in language, according to a study published in November in The American Journal of Human Genetics.

Individuals with attention deficit hyperactivity disorder (ADHD) have a higher rate of DNA duplications and deletions, including some in regions linked to autism and schizophrenia, according to a study published 23 October in The Lancet.