Attention-deficit/hyperactive disorder (ADHD) and narcolepsy may share genetic links, according to an analysis of polygenic risk scores published online in the journal Translational Psychiatry.
“We found that the genetic risk for narcolepsy has a significant association with ADHD traits using data from the general population,” researchers wrote. “Specifically, both hyperactivity and inattention traits were significantly associated with narcolepsy polygenic risk scores, suggesting that these disorders have a close genetic association.”
Investigators calculated polygenic risk scores for individuals using data from a previously collected genome-wide association study of narcolepsy and essential hypersomnia. They looked for a possible genetic link between ADHD and narcolepsy traits in 876 mothers and children from the Japanese Hamamatsu Birth Cohort.
Although narcolepsy polygenic risk scores were significantly linked with ADHD traits in the hyperactivity and inattention domains, essential hypersomnia polygenic risk scores were not significantly associated with either ADHD domain, according to the study.
Using gene-set enrichment analyses, researchers also identified common molecular pathways underlying both ADHD and narcolepsy, such as dopamine signaling, immune system regulation, glial cell function, and iron metabolism.
“Findings indicate that ADHD and narcolepsy are genetically related, and there are possible common underlying biological mechanisms for this relationship,” researchers wrote. “Future studies replicating these findings would be warranted to elucidate the genetic vulnerability for daytime sleepiness in individuals with ADHD.”
Takahashi N, Nishimura T, Harada T, et al. Polygenic risk score analysis revealed shared genetic background in attention deficit hyperactivity disorder and narcolepsy. Translational Psychiatry. 2020;10(1):284.