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 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, points out. The Mount Sinai team worked in collaboration with the Consortium conducting the Population-Based Autism Genetics and Environment Study (PAGES) study to conduct this analysis of DNA sequence variations. The objective was to clarify the contribution and interactions of genetics and other environmental factorsin the development of the disease.
More than 50% of autism risk attributable to hereditary variations
Conducted 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 the two groups. About 52.4% of autism risk 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 indeed an underlying family risk. Rare genetic factors add to the common factors and trigger the disease in a particular family member. These are called de novo mutations, the gene mutates when neither parent has it in their genetic heritage.
The impact on the risk ofautism of genetic variation present in most people remains difficult to assess, say the researchers, 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.
