Genetics? Environmental ? The origins of autism are still poorly understood. A recent study, published in the journal Nature Genetics and conducted by a team of researchers from the Mount Sinai School (New York) suggests that susceptibility to autism is hereditary.
In any case, this is what Professor Joseph D. Buxbaum, director of the Seaver Autism Center and professor of psychiatry at the Mount Sinai School of Medicine, emphasizes. The Mount Sinai team worked in collaboration with the Consortium leading the Population-Based Autism Genetics and Environment Study (PAGES) to conduct this analysis of DNA sequence variations. The aim was to clarify the contribution and interactions of genetics and other environmental factors, in the development of the disease.
Over 50% risk of autism attributable to hereditary variations
Carried out on nearly 3,000 cases of autism spectrum disorder (ASD) as well as on unaffected subjects, the researchers observed a large part of the genetic variants linked to the disease, in both groups. About 52.4% of the risk of autism is attributable to both common and rare hereditary variations. Spontaneous mutations represent only 2.6% of the risk.
The researchers explain it clearly: there is an underlying family risk. Rare genetic factors are added to common factors and trigger the disease in a particular family member. They are called de novo mutations, the gene mutates when neither of the parents has it in their genetic heritage.
The impact on the risk ofautism genetic variations present in most people remains difficult to assess, the researchers say, due to limited sample sizes. Although these spontaneous mutations represent only a small fraction of the risk, they are important clues to understanding the molecular basis of the disease.
