Gene may hold key to understanding autism

One of the largest studies into the causes of autism has identified a gene that could have a serious effect on the development of the disorder.

Researchers hope the discovery of the role of neurexin 1 in autism will eventually allow them to unravel the causes of the disorder and help develop genetic testing to diagnose a pre-disposition to the illness.

The Autism Genome Project (AGP), which involves 120 scientists from 19 countries, said neurexin 1 was part of a family of genes thought to be important in the communication of messages between cells.

The study, which confirms existing research suggesting that autism is a largely genetic condition, also revealed that a previously unidentified region of chromosome 11 could be linked to the disorder. Chromosomes are thread-like structures that contain the genetic material DNA, inside the body's cells.

Autism is a developmental disability that affects the way a person communicates and relates to people around them. Sufferers, 80 per cent of whom are male, have difficulties with everyday social interaction and their ability to develop friendships is generally limited, as is their capacity to understand other people's emotional expression. It affects about 588,000 people in the UK, according to the National Autistic Society.

The researchers, including teams from Britain, studied nearly 1,200 families with two or more people with autism. The findings are published today in the journal Nature Genetics and add to the evidence that tiny, rare variations in genes may heighten the risk of autism.

The study used two techniques to examine the DNA of the families that had a history of autism.

So-called "gene chip" technologies were used to look for genetic similarities among affected families. In addition, scientists scanned the same DNA to look for variations in the make-up.

Those variations are tiny insertions and deletions of genetic material that scientists believe may be involved in autism and other common diseases.

The AGP researchers found a number of variations in the genetic material of people with autism.

In the UK, work was carried out at the University of Manchester, the Institute of Psychiatry at King's College, London, and the University of Oxford.

Professor Jonathan Green, a child psychiatrist who led the Manchester team, said: "We hope that these exciting results may represent a step on the way to further new treatments in the future."

Professor John Burn, Medical Director and head of Institute of Human Genetics, University of Newcastle, said: "This is fantastic news. We have been waiting for the log jam to break on this for several years. There will almost certainly be an interaction between several genes so this one discovery doesn't provide a complete answer but it could be a key step in development for effective treatments as it provides a target for drug development."

Benet Middleton, director of communications at the National Autistic Society, said: "Research into the genetic causes of autism is ongoing but the potential benefits for diagnosis and treatment are still many years away. It is absolutely crucial that there are services in place to support these people and their families."