Gene clue in autism research

Variations in a gene involved in energy production could be linked to autism, US researchers say. A team based at the Mount Sinai School of Medicine in New York studied 720 people from 411 families, who all have either autism, or the related condition autistic disorder. They found that variations in a gene that makes a protein involved in producing the cell's 'fuel' molecule, ATP (adenosine triphosphate), appeared to double the risk of autism. While previous studies have linked rare genetic mutations to autism in individual families, this is the first to identify a genetic susceptibility that affects a broad population, the study authors say. Their findings, published in the American Journal of Psychiatry, suggest that disruption to the brain cells' fuel supply could stop them from working normally.

Autism is a lifelong developmental disability that typically appears during the first three years of life. The disorder affects social and language skills, and the way in which a child relates to people, objects and events. Autism often runs in families, suggesting that it has a genetic basis, although it is thought that the combined effects of at least 5-10 different genes are involved. The gene variants identified in the latest study appear to increase the risk of developing autism by 2-5 times, although the authors stress that further work is needed to confirm the link. 'It looks like they might have something... but it's a bit too soon to say definitively', commented Susan Santangelo, of Harvard University.

The gene, called SLC25A12, makes a protein called the mitochondrial aspartate/glutamate carrier, which is involved in the production of ATP. Genetic mutations that affect the rate of ATP-production could disrupt the supply of the large amounts of energy required by the brain, which in turn could trigger the symptoms of autism, the authors speculate. Inheriting these gene variants is not in itself enough to cause the disorder, although they do appear to double a person's risk. Lead author Joseph Buxbaum says that 'it is an accumulation of genetic factors that cause the disease', adding 'our current challenge is to find more of these genes'.