DNA Methylation Studies in CREW Cohorts (URECA and COAST)

Children's Respiratory Environment Workgroup (CREW) is an NIH-funded project consisting of 12 individual U.S. cohorts and three scientific centers working together to identify phenotypes and causes of childhood asthma. CREW includes data from a large number of children and their families, with broad diversity in terms of ethnicity, family characteristics, neighborhoods and geographic locations. In this study, we identified differentially methylated regions from whole-genome bisulfite sequencing (WGBS) in nasal epithelial cells from 39 children of European or African ancestries, and with or without allergic asthma. Study participants were from two of the CREW cohorts: the Urban Environment and Childhood Asthma (URECA) cohort and the Childhood Origins of Asthma (COAST) cohort.The URECA children are also participants of a larger genetic study, in which DNA samples are derived from blood. That data is presented in the "Whole Genome Sequencing in the Inner City Asthma Consortium (ICAC) Cohorts - phs002921" study.]]>
We first selected individuals with parent-reported race: black in URECA or white in COAST, and then confirmed African admixed or European ancestries by principal components analysis. Case Inclusion: The participants with allergies and asthma were required to have both atopy and wheezing in the first 3 years of life and asthma diagnosed at age 6 (COAST) or age 7 (URECA). They were age 18-20 in COAST or age 11 in URECA at the time of sampling. Control Inclusion: The participants without allergies and asthma were required to have none of the 3 phenotypes (atopy, wheeze, asthma) at any age until the time of sampling. From these individuals with sufficient DNA for methylation studies on the 2 platforms (EPIC and Booster), we then selected 20 individuals from each cohort, so that the participants with or without asthma were balanced for sex. Later, one participant in COAST was excluded from further analysis due to a sample error. ]]>