New research, published in the journal Nature Genetics, has identified 12 DNA segments that may increase the risk of developing ADHD.
Benjamin M. Neale of Harvard Medical School in Boston, Anders D. Børglum of Aarhus University in Denmark, and Stephen V. Faraone of the State University of New York led the international team working on this research.
As the authors explain in their article, ADHD is “a highly inherited childhood behavior disorder.” For this reason, there are numerous genetic variants that increase the risk of ADHD. Although researchers believe that 74% of the risk of ADHD is genetic, they had not yet linked any genes in detail with the disorder. Up to now.
The researchers examined the genomes of more than 50,000 people around the world , including more than 20,000 people with a diagnosis of ADHD. In all, they analyzed about 10 million genetic markers.
Study is the first to find 12 genetic locations
Bru Cormand, co-author of the work and head of the Neurogenetics Research Group at the University of Barcelona (Spain), affirms that the team found common genetic variants, called single nucleotide polymorphisms (SNPs), which represent 21% of the total genetics of ADHD “.
“Furthermore, most of the genetic alterations that were identified are found in regions of the genome that have been maintained throughout evolution, highlighting their functional relevance.”
Specifically, the researchers identified 12 genomic segments that could make a person susceptible to ADHD . Many of the genetic changes that ADHD involves affect the expression of certain genes in the brain, experts say.
For example, one of the DNA fragments corresponds to FOXP2, a gene that plays a key role in the development of human language. FOXP2 encodes a protein that helps create neuronal synapses and thus facilitates learning.
The study found a second gene called DUSP6. This gene contributes to the regulation of dopamine, a neurotransmitter that makes learning possible.
Finally, the researchers also identified the SEMA6D gene as one that appears to increase the risk of ADHD. SEMA6D expression occurs during embryo development, and some researchers believe that it helps develop neural branches.
Overall, the study found that ADHD shares a genetic background with several other psychiatric and non-psychiatric conditions.
“The results reveal a genetic overlap between ADHD and major depression, anorexia, educational level, obesity, reproductive success, smoking or insomnia, among others. The study reinforces the idea that ADHD is a a disorder with a strong biological basis, where genetics means a lot, “explains Cormand.
This study is the first to begin to identify the specific genes that are associated with ADHD risk.
“These results show the importance of promoting large-scale studies, which are only possible through large international consortia, to explore the genetic basis of complex brain diseases,” concludes Cormand.
Reference: Discovery of the first genome-wide significant risk loci for attention deficit / hyperactivity disorder. Ditte Demontis, Raymond K. Walters, Benjamin M. Neale
Nature Genetics (2018) | DOI: https://doi.org/10.1038/s41588-018-0269-7
