Intra-individual Change Over Time in DNA Methylation With Familial Clustering

To determine whether there are longitudinal changes in global DNA methylation in individuals and to evaluate whether methylation maintenance demonstrates familial clustering. DESIGN, SETTING, AND PARTICIPANTS: We measured global DNA methylation by luminometric methylation assay, a quantitative measurement of genome-wide DNA methylation, on DNA sampled at 2 visits on average 11 years apart in 111 individuals from an Icelandic cohort (1991 and 2002-2005) and on average 16 years apart in 126 individuals from a Utah sample (1982-1985 and 1997-2005). MAIN OUTCOME MEASURE: Global methylation changes over time.

Twenty-nine percent of Icelandic individuals showed greater than 10% methylation change over time (P