Important Breakthrough In Our Understanding Of Autism Risk
The causes of autism and autism spectrum disorder (ASD) are complex, and contain elements of both nature (genes) and the environment. New research published in BioMed Central's open access journal Molecular Autism shows that common genetic polymorphisms (genetic variation) can add up to an increased risk of ASD.
The contribution of inheritance and genetic mutation versus environmental factors to the risk of ASD is hotly debated. Most twin studies show the contribution heavily tilted toward inheritance, but the exact amount of involvement of genes in ASD risk is less apparent. This is because, while the impact of rare genetic variations on ASD risk is becoming clear, the role of more common variations, so called single nucleotide polymorphisms (SNP), remains unresolved.
Researchers analyzed one million of the common gene variations in each participant's genome and determined that in families with only one affected child, heredity was the root cause of 40%, the other 60% are presumed environmental in nature. Families where more than one child has autism see these numbers flipped. The chance of heredity being the root issue increases to 60% in these cases.