Are Autism Genes Present In All?

Studying the genetic relationship between autism spectrum disorders (ASD) and ASD-related characteristics in the larger population, experts found that genetic risks relating to ASD, including variants that have been inherited, but not noticed in the parents, tend to influence a number of behavioral and developmental traits.

 Thus, those who have been said to have ASD would reflect these characteristics, according to researchers from the University of Bristol, the Broad Institute of Harvard, MIT and the Massachusetts General Hospital (MGH).

"There has been a lot of strong but indirect evidence that has suggested these findings," said co-director of the Broad Institute's Medical and Population Genetics (MPG) Program and senior study author Mark Daly. "Once we had measurable genetic signals in hand - both polygenic risk and specific de novo mutations known to contribute to ASD - we were able to make an incontrovertible case that the genetic risk contributing to autism is genetic risk that exists in all of us, and influences our behavior and social communication."

Information was collected from unaffected persons from a general population cohort (the Bristol-based Avon Longitudinal Study of Parents and Children) and a nuclear family cohort (Simons Simplex Collection) of ASD cases and siblings who are not affected.

The ASD collections were part of many global autism genetic studies based on the Psychiatric Genomics Consortium Autism group, or the iPSYCH autism project in Denmark, the SSC and the Autism Sequencing Consortium.

"Many traits that related to disease risk - like blood pressure or cholesterol levels - demonstrate a similar continuum of risk, with contributions from common and rare genetic variants, plus environmental and chance events," said professor George Davey Smith, co-author and scientific director of ALSPAC. "The present study demonstrates how this continuum applies to a condition generally thought of as either existing or not."

The approach can be used to study the associations between genetic risk and behavioral traits affecting neuropsychiatric disorders, such as schizophrenia.

About one in 68 children and one in 42 boys are affected, said Autism Speaks. Such patients have difficulties in communicating, as well as language problems.

The study was published today in the journal Nature Genetics.