19 Feb 07

The world's largest search for genes linked to autism, to which Oxford University was an important contributor, has uncovered new mutations believed to raise a child's risk of developing the brain disorder.

The first phase of the Autism Genome Project (AGP), a collaboration of more than 120 scientists at 50 institutions worldwide, searched for relevant genes in scans of DNA from nearly 1,200 families with two or more children affected by autism. The consortium used 'gene chip' technology to look for genetic similarities in autistic people, and searched DNA for copy number variations, in which there is either an extra or missing copy of a gene.

One of the biggest contributors to the AGP, contributing 280 families, is the International Molecular Genetic Study of Autism Consortium (IMGSAC), which is led by Professor Tony Monaco from Oxford's Wellcome Trust Centre for Human Genetics and Professor Anthony Bailey from Oxford's Department of Psychiatry.

The first phase of the AGP, the results of which were published in Nature Genetics , found two new mutations linked to autism - one in an unknown gene on chromosome 11, and the second a defect in a gene which codes for a protein called neurexin 1, which works with a brain messenger chemical called glutamate to enable neighbouring neurons to communicate with one another.

The $14.5m second phase of the project has now been launched and is due to begin this year. Professor Monaco led the funding bid.Researchers will now focus on the genes identified and conduct a more intense search for other genetic factors.