An international team of researchers has uncovered numerous genes that are associated with autism. The findings, published in the journal Nature, could lead to new ways of diagnosing and treating the condition. The study was partly funded by the EU through the AUTISM MOLGEN ('Using European and international populations to identify autism susceptibility loci') project, which was supported under the 'Life sciences, genomics and biotechnology for health' Thematic area of the Sixth Framework Programme (FP6) with almost EUR 2 million to identify susceptibility alleles for autism spectrum disorders. Autism spectrum disorders generally become apparent in early childhood and are characterised by highly repetitive behaviour, difficulties with social interactions and communication, and restricted interests. Although scientists have known for a long time that autism has a strong genetic component, pinning down the genes involved has proven tricky. In this study, scientists compared the genomes of around 1,000 people with autism spectrum disorders to the genomes of over 1,200 people who did not have autism. They were looking for areas of the genome where whole stretches of DNA (deoxyribonucleic acid) had either been duplicated or deleted. These 'copy number variants' (CNVs) may include as many as 20 genes, and the team suspected that some rare CNVs could be behind many cases of autism. The research revealed that the people with autism spectrum disorders had an average of 19% more CNVs that disrupt genes than the people in the control group. Many of the lost and duplicated sections of DNA were located in regions of the genome that are already known to be implicated in autism. However, many of the CNVs disrupted genes have never been linked to autism before. These newly-discovered autism genes turned out to be involved in processes such as nerve cell proliferation in the brain and the transmission of signals between nerve cells in the brain. Furthermore, some of the CNVs associated with autism have previously been found to be associated with learning disabilities. There may even be some overlap with conditions like epilepsy and schizophrenia. 'Disruption of genes through rare losses or duplications of whole stretches of DNA is more common among people with autism spectrum disorders, especially in regions of our genomes that we already know to be important in autism,' commented Dr Alistair Pagnamenta of Oxford University in the UK, one of the lead authors of the paper. 'This is good evidence that this type of genetic variation is important to understanding the causes of this condition.' 'With further research work, these and other recent findings have very real potential to lead to the development of novel interventions and treatments for these disorders,' added Professor Michael Gill of Trinity College Dublin in Ireland. The work was carried out under the auspices of the Autism Genome Project, an international research effort bringing together scientists in Europe, Canada and the US. Some of the researchers involved in this study are now planning to use the findings to develop a genetic test for autism. Such a test could confirm the diagnosis of an autism spectrum disorder and aid in decisions regarding care and support. 'Just knowing about these genetic changes can help the families involved come to terms with why their child has autism, but it can also be important where there are siblings too in determining future risk,' explained Professor Tony Monaco of Oxford University.