Among neurodevelopmental disorders, ADHD and autism are very similar: Both in terms of being one of the most common child psychiatric diagnoses, and being highly heritable. While the core symptoms are different, both conditions have appreciable similarities in their underlying genetic causes.
Researchers have now found seven genetic variants that are found in both ADHD and autism, as well as five genetic variants that are specific to only one of the two conditions. The results were published in Nature.
In this study, researchers assessed the genetic variations in the genomes of 34,462 people with autism spectrum disorder and/or ADHD, as well as 41,201 controls without either diagnoses. What they uncovered is both shared risk and gene-based variations which distinguish these two disorders from each other. “We have succeeded in identifying both shared genetic risk variants and genetic variants that differentiate the two developmental disorders,” says Professor Anders Børglum of the Department of Biomedicine at Aarhus University and iPSYCH, Denmark’s largest research project within psychiatry, which is behind the study via a press release about the study.
“That means that we are beginning to understand both the biological processes that are behind the development of both diagnoses, and – as something completely new – also the processes that push the developmental disorder specifically in the direction of either autism or ADHD.”
The findings, researchers hope, will make it possible to render more accurate diagnoses to yield earlier interventions in both disorders, so that all patients receive a precise, and personalized treatment plan.
“The autism diagnosis is typically made before an ADHD diagnosis. So if, for example, the person is also hyperactive and finds it difficult to concentrate, this may well be slightly drowned out by the autism symptoms, and we may not see the ADHD challenges,” said Prof. Børglum.
“But if we have a genetic study of a person with an autism diagnosis, and we see a major genetic load of ADHD genetics, then it may be that we should monitor that person a bit more closely. In this way, we can in the future become quicker to spot the development and give the family good tools to handle this diagnosis, too.”