In recent years, different studies have provided evidence about the connection of epigenome and autoimmune diseases like MS.6,10 DNMT3B protein is one of the MT enzymes creating a new methylation pattern on DNA by de novo methylation.7 The common SNP of this gene, -579G>T, is a G to T transition in promoter (-579 bp from exon 1B transcription site).16 The functional role of the DNMT3B-579G>T polymorphism is controversial. Here, MCAT is linked to autoimmune disease.