By Dorta Associates | January 31, 2019 at 02:01 PM EST | No Comments
An important study was just published in Nature Genetics. The researchers obtained large samples with over 20,000 either clinically diagnosed or self-identified patients with ADHD whose genes we could compare to 35,000 non-diagnosed individuals. In these large gene data sets, the study used state of the art genetic modeling to map 12 key gene locations related to ADHD. These locations are generally consistent with other smaller studies which is important since it supports the generalizability of the gene loci with varied samples.
They identified 12 gene loci (for about 22% of the gene heritability in ADHD) and a clustering of genes on chromosome 1. The study firmly supports the polygenetic model of ADHD (multiple risk genes have to be present to have the disorder).
The genes mapped are known to be related to varied self-regulation processes and neurodevelopmental factors including dopamine levels in the brain, neuronal migration, synapse formation and language development.
The study also supports that ADHD symptoms are an extreme expression of normal behaviors. The highly heritable genes mapped have adapted with evolution to be resistant to mutation and loss of function. This supports that ADHD is a disorder where its the abnormal "quantity" of expression of a behavior to a situational demand that is the problem.
The identified genes are also related to adverse health outcomes including smoking, depression, obesity, diabetes, and a range of other impulse related problems.
The study also linked ADHD with difficulties in school including completing less formal schooling.