The first epigenome-wide study in BD was carried out by Hughes T et al. In their study, they analyzed the genome-wide DNA methylation patterns of monocytes and CD4+ T cells and found significantly different methylation sites between untreated BD patients and controls: 383 CpG sites in 228 genes in monocytes (129 hypermethylated and 254 hypomethylated) and 125 CpG sites in 62 genes in CD4+ T cells (67 hypomethylated and 58 hypermethylated). The gene discussed is CD4; the disease is Behcet disease.