Abstract
AbstractBackgroundAttention deficit hyperactivity disorder (ADHD) is highly heritable, but little is known about the relative effects of transmitted (i.e. direct) and non-transmitted (i.e. indirect) common variant risks. Using parent-offspring trios, we tested whether polygenic liability for neurodevelopmental and psychiatric disorders and lower cognitive ability is over-transmitted to ADHD probands. We also tested for indirect or ‘genetic nurture’ effects, by examining whether non-transmitted ADHD polygenic liability is elevated. Finally, we examined whether complete trios are representative.MethodsPolygenic risk scores (PRS) for ADHD, anxiety, autism, bipolar disorder, depression, obsessive-compulsive disorder (OCD), schizophrenia, Tourette’s syndrome, and cognitive ability were calculated in UK controls (N=5,081), UK probands with ADHD (N=857), and, where available, their biological parents (N=328 trios), and also a replication sample of 844 ADHD trios.ResultsADHD PRS were over-transmitted and cognitive ability and OCD PRS were under-transmitted to probands. These results were independently replicated. Over-transmission of polygenic liability was not observed for other disorders. Non-transmitted alleles were not enriched for ADHD liability compared to controls. Probands from incomplete trios had more hyperactive-impulsive and conduct disorder symptoms, lower IQ, and lower socioeconomic status than complete trios. PRS did not vary by trio status.ConclusionsThe results support direct transmission of polygenic liability for ADHD and cognitive ability from parents to offspring, but not for other neurodevelopmental/psychiatric disorders. They also suggest that non-transmitted neurodevelopmental/psychiatric parental alleles do not contribute indirectly to ADHD via genetic nurture. Furthermore, ascertainment of complete ADHD trios may be non-random, in terms of demographic and clinical factors.
Publisher
Cold Spring Harbor Laboratory