While one main risk gene may make an individual susceptible to autism or another neurodevelopmental disorder, it is the whole collection of associated changes in their DNA that decides whether they develop it and how severe it becomes.
This was the conclusion that researchers arrived at after analyzing developmental, cognitive, and genome sequencing data of hundreds of people with known risk genes together with that of their parents and siblings.
They suggest that their findings explain why two people carrying the same risk gene, also known as the “primary mutation,” can have very different symptoms of the associated neurodevelopmental disorder.
“For example,” says senior study author Santhosh Girirajan, an associate professor of biochemistry and molecular biology at Pennsylvania State University in University Park, “when a parent and child have the same primary mutation but only the child develops the disorder.”
He explains that when diagnosing a disorder such as autism, the focus on finding the cause tends to be on identifying the “one primary mutation.”
However, this approach does not explain why many people with the same primary mutation can have widely different symptoms.
Source: Autism prognosis: Parental genes ‘incredibly useful’ : Medical News Today