Researchers reveal genetics behind autism

One of the most common genetic alterations in autism -- deletion of a 27-gene cluster on chromosome 16 -- causes autism-like features, according to scientists at Cold Spring Harbor Laboratory (CSHL).

By generating mouse models of autism using a technique known as chromosome engineering, CSHL Professor Alea Mills and colleagues provide the first functional evidence that inheriting fewer copies of these genes leads to features resembling those used to diagnose children with autism.

“Children normally inherit one copy of a gene from each parent. We had the tools to see whether copy number changes found in kids with autism were causing the syndrome,” said Mills.

After engineering mice that had a chromosome defect corresponding to the human 16p11.2 deletion found in autism, Mills and her team analysed these models for a variety of behaviours, as the clinical features of autism often vary widely from patient to patient, even within the same family.

“Mice with the deletion acted completely different from normal mice,” explained Guy Horev, a Postdoctoral Fellow in the Mills laboratory and first author of the study.

These mice had a number of behaviours characteristic of autism: hyperactivity, difficulty adapting to a new environment, sleeping deficits, and restricted, repetitive behaviours.

Interestingly, mice that had been engineered to carry an extra copy, or duplication, of the 16p11.2 region did not have these characteristics, but instead, had the reciprocal behaviours.

The study appeared in the Proceedings of the National Academy of Sciences in the early online edition during the week of October 3.