Genome-wide DNA methylation analysis in peripheral blood of monozygotic twins informative for psychopathology

Peripheral blood from thirty-four monozygotic twin subjects from the general population (n = 17 twin pairs) was collected for epigenomic analysis via Illumina Infinium HumanMethylation450 Beadchip. All subjects were screened for DSM-IV based criteria for both current and lifetime psychiatric disorders. Out of 17 twin pairs, there were: 7 healthy twin pairs where none of the twins of a pair met criteria for any DSM-IV disorder; 6 discordant twin pairs where only one of the twins of each pair met diagnostic criteria; and 4 concordant twin pairs where both twins of a pair met clinical DSM-IV based criteria. Bisulphite converted DNA from the 34 samples (17 twin pairs) were hybridised to the Illumina Infinium Human Methylation450 Beadchip