Data Resource Profile: Whole-Blood DNA Methylation Resource in Generation Scotland (MeGS)

Data resource basicsMethylation in Generation Scotland (MeGS), which was initiated in 2016, was established to allow the integration of whole-blood DNA methylation data with the rich phenotypic, genetic, and electronic health record linkage already available for Generation Scotland (GS): a population-and family-based cohort (N 24 096 from 6862 families) [1][2][3].DNA methylation is an epigenetic modification influenced by both genetic and environmental factors, making it an attractive candidate for investigating mechanisms underlying complex traits and Key Features We have generated whole-blood DNA methylation profiles from 18 869 Generation Scotland: Scottish Family Health Study (GS) participants, resulting in, at the time of writing, the largest single-cohort DNA methylation resource for basic biological and medical research: Methylation in Generation Scotland (MeGS). GS is a community-and family-based cohort, which recruited >24 000 participants from Scotland between 2006 and 2011.Comprehensive phenotype information, including detailed data on cognitive function, personality traits, and mental health, is available for all participants.The majority of GS participants (83%) have genome-wide single-nucleotide polymorphism genotype data (Illumina HumanOmniExpressExome-8 array v1.0 and v1.2). Over 97% of GS participants have given consent for health record linkage and re-contact. At baseline, blood-based DNA methylation was characterized at 850 000 sites across four waves by using the Illumina EPICv1 array.MeGS participants were aged between 17 and 99 years at the time of enrolment in GS. Blood-based DNA methylation EPICv1 array profiles collected at a follow-up appointment that took place 4.3-12.2years (mean 7.1 years) after baseline are also available for 796 MeGS participants.