biostudies-literatureAssary EEuropean Research CouncilNIA NIH HHSEPANIMH NIH HHSDutch Research Council (NWO)NIAAA NIH HHSWellcome Trust1683-1696https://www.ebi.ac.uk/biostudies/studies/S-EPMC12367547biostudies-literatureUnknown9(8)Individual sensitivity to environmental exposures may be genetically influenced. This genotype-by-environment interplay implies differences in phenotypic variance across genotypes, but these variants have proven challenging to detect. Genome-wide association studies of monozygotic twin differences are conducted through family-based variance analyses, which are more robust to the systemic biases that impact population-based methods. We combined data from 21,792 monozygotic twins (10,896 pairs) from 11 studies to conduct one of the largest genome-wide association study meta-analyses of monozygotic phenotypic differences, in children, adolescents and adults separately, for seven psychiatric and neurodevelopmental phenotypes: attention deficit hyperactivity disorder symptoms, autistic traits, Nature human behaviourGenetics of monozygotic twins reveals the impact of environmental sensitivity on psychiatric and neurodevelopmental phenotypes.PMC12367547P01 AG008761R01 AG059329K05 AA000145R01 AA009203R01 AG008724208881/Z/17/ZR01 AG037985R01 AA015416208806/Z/17/ZR01 AA012502R01 AG050595R01 AG017561R01 AG010175R37 AA012502R01 MH130448R01 AG060470R01 AG046938EP-C-15-001480-15-001771057K02 AA018755R01 AG028555Palviainen TThalamuthu ATrollor JNCheesman RArmstrong NJReynolds CAKaprio JHavdahl AAmes DMartin NGColeman JRIWright Mde Geus EGordon SAsk HLarsson HPlomin RPaige Harden KTaylor MMedland SEChen ZMagnus PHammond CJLatvala AHemani GNygaard MOrdonana JRWalters RGBartels MHowe LJColodro-Conde LLi LEvans DAssary EVuoksimaa ELi SAkingbuwa WArchie CGrasby KLMengel-From JCatts VSLin KBenjamin DJKeller MCChristensen Kvan de Weijer MPOskarsson SSachdev PSMillwood IYPyun HTorvik FAWilloughby EAMallard TMunroe PBKeers RWithin Family ConsortiumMorris SMadrid-Valero JJBoivin MEley TCHughes AMPedersen NLBrodaty HBrescianini SHottenga JJTucker-Drob EMSung JLee SJLichtenstein PBoomsma DIPingault JBDavies NMLundstrom SHuider FMather KAAhlskog RGiannelis AAsvold BOLim KHill WDLee TKarlsson RfalseGenetics of monozygotic twins reveals the impact of environmental sensitivity on psychiatric and neurodevelopmental phenotypes.Individual sensitivity to environmental exposures may be genetically influenced. This genotype-by-environment interplay implies differences in phenotypic variance across genotypes, but these variants have proven challenging to detect. Genome-wide association studies of monozygotic twin differences are conducted through family-based variance analyses, which are more robust to the systemic biases that impact population-based methods. We combined data from 21,792 monozygotic twins (10,896 pairs) from 11 studies to conduct one of the largest genome-wide association study meta-analyses of monozygotic phenotypic differences, in children, adolescents and adults separately, for seven psychiatric and neurodevelopmental phenotypes: attention deficit hyperactivity disorder symptoms, autistic traits, 2025-01-01T00:00:00Z2025 Aug2026-05-29T17:17:03.355Z2026-04-08T05:25:06.844ZS-EPMC123675474049490110.1038/s41562-025-02193-7