DNA methyltransferase refers to a family of enzymes responsible for the transfer of a methyl group to DNA molecules. The modification of DNA through the addition of a methyl group can have significant impacts on gene expression, development, and disease. A few synonyms for DNA methyltransferase include DNA methylase, DNMT, M.DnaJ, and CpG methyltransferase. These terms all refer to enzymes that catalyze DNA methylation and play important roles in epigenetic regulation. While there are several forms of DNA methyltransferase, the most well-known are DNMT1, DNMT2, and DNMT3A and DNMT3B, each with their unique functions. Overall, DNA methyltransferase is an essential player in maintaining genomic stability and regulation.