We performed sodium bisulfite pyrosequencing to validate the microarray findings in the human sample at CpG dinucleotides located within the region chr 1: 20 986 692–20 986 676 (strand −, human genome build hg18) and chr 19: 45 416 573 (strand +, human genome build hg18), located upstream of HP1BP3 and TTC9B, respectively. PPD status was significantly associated with the HP1BP3 microarray and pyrosequencing data and was significantly correlated between methods (Figures 2a–c and Table 2). DNA methylation for TTC9B was significantly associated with PPD status for both the microarray and pyrosequencing data and was significantly correlated between the two methods (Figures 2e–g and Table 2).
