A scientific study published on the journal Molecular Psychiatry (doi:10.1038/mp.2013.106) identifies new genes involved in autism, a polygenic disorder that is difficult to diagnose and treat. Researches Bru Cormand, Claudio Toma, Bàrbara Torrico and Alba Tristán, researches from the Institute of Biomedicine of the UB (IBUB) and Mònica Bayés, from the National Centre for Genome Analysis (CNAG) –located at the Barcelona Science Park (PCB-UB)– have collaborated in this study. To identify the genes associated with autism spectrum disorders is fundamental to find targets to develop effective treatments for patients. It is necessary to promote new projects to define patients' genetics, identify which are the most important genes and develop new genetic diagnosis tools.

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Autism spectrum disorders (ASDs) represent a group of neurodevelopmental disorders which affect one out of 80-100 children. Autism’s aetiology remains mainly unknown but there is strong evidence that genetic factors play a major role. An active international research has been carried out for several years in order to identify candidate genes which explain the origin and development of the disease.

Bru Cormand, head of the Research Group on Neurogenetics at the Department of Genetics of the UB, affirms that “studies made with monozygotic (genetically identical) and dizygotic twins show that genetic factors play a major role in the aetiology of the disease”. Therefore, “if a monozygotic twin has autism, the likelihood that the other twin also has the disease is 60-90%; however, if they are dizygotic twins, the probability is reduced up to 20%”, states the expert. This proves that genetic factors play a major role in the aetiology of the disease, but the association between the disease and one person’s set of mutated genes remains uncompleted.

To date, studies on autism genetics were mainly focused on de novo mutations —the ones that appear in a child but they are not present in progenitors— in families with one child affected. However, the work published on Molecular Psychiatry and first signed by the expert Claudio Toma provides an innovative view on the study of ASDs genetics: “It is the first time that mutations transmitted to children by any of the progenitors are studied in a genomic perspective. In total, ten families in which two or three children have autism were analysed”, details Bru Cormand.

The research shows that children need to inherit a certain number of variants in order to develop autism. “Inherited genetic factors may have a cumulative effect; therefore, the disease would only appear if a certain number of variants are inherited”, explain researchers. Interaction between different affected genes may also occur; this should be investigated in the future.

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