Autism gene hunt narrows

Scientists are closing in on the handful of genes linked to autism - by eliminating those not connected with the condition.

They hope that within two years, their efforts will identify most of the genetic "faults" which contribute to its development.

Current thinking suggests there are at least four, and perhaps as many as 10 genes which play a role in autism.

Autism is an umbrella term for a large number of similar "developmental disorders".

All clear for genes
These normally strike in the first few years of life, and severely curtail social and communication skills.

"We hope that in about two years, we can find these genes"

Professor Anthony Monaco, Oxford University

Autistic children, in general, find it much harder to relate to the outside world.

Four studies into the genetic roots of autism have been published on Monday in the journal Molecular Psychiatry.

Three of them look into genes previously suspected of playing a part - but have given them the all-clear.

Only one adds to positive evidence that a particular gene is involved.

This reflects the pattern of research across the world - studies pointing conclusively to one or more genes have proved elusive.

Scientists are fairly certain that they have found a few tiny regions among the millions of genes on human DNA which hold the key.

However, each of these carries hundreds of individual genes, and their work now is to painstakingly pick out and test these one by one.

Professor Anthony Monaco, Director of The Wellcome Trust Centre for Human Genetics at the University of Oxford, co-authored one research paper published on Monday.

This ruled out four potential autism genes located on one particular tiny region of the cell's DNA.

Hard work
He said: "It's pretty labour intensive work, and in this instance, hasn't come up with anything particularly exciting.

"Computer models suggest that there are somewhere between three and 10 genes involved in the development of autism.

"We are encouraged by the fact that we have narrowed the search down to two or three regions.

"We hope that in about two years, we can find these genes. If we don't do it, someone else will by then."

However, finding the genes, while important, is only the first step towards finding ways to help autistic children, and their parents.

It is likely that other things have a bearing on the development of the condition - as yet unidentified "environmental" factors which may help trigger the decline, or how severe the autism is in any child.