Longitudinal Study of Genome-Wide DNA Methylation from Birth to the First Two Years of Life

• Activity Number: 301
• Type: Contributed
• Date/Time: Tuesday, August 2, 2011 : 8:30 AM to 10:20 AM
• Sponsor: Biometrics Section
• Author(s): Deli Wang*+ and Xin Liu and Ying Zhou and Xiumei Hong and Xiaobin Wang
• Companies: Northwestern University and CMRC, Children's Memorial Hospital and Northwestern University and CMRC, Children's Memorial Hospital and CMRC, Children's Memorial Hospital
• Keywords: DNA methylation ; Genome-wide ; DIP test ; VMS ; Normal mixture ; Empirical Bayes

Abstract

To date, epigenome profiles at birth and in early life are largely unexplored. We performed epigenomic mapping in 105 children(59 boys and 46 girls) enrolled at Boston Medical Center at birth(cord blood) and within the first 2 years of life(venous blood) using Illumina Infinium Human methylation27 BeadChip to address two questions: 1. What is the pattern of genome-wide DNA methylation profiles at birth and in the first 2 years of life? 2. Whether the DNA methylation patterns vary by gender and genomic locations over time. Batch effects were adjusted using an empirical Bayes method.The DIP test,kurtosis and skewness were used to classify methylation distributions. A normal mixture model was applied to classify varied methylated sites(VMS). We identified six major types of distributions of the 27K probes and found significant genome-wide methylation changes within the first two years of life throughout the genome.However,the changes were not significantly different between boys and girls except for X chromosome.We also found that methylation levels and longitudinal changes vary by CpG island and gene structure.We identified top 50 probes which have important biological function.