Mutations in tet methylcytosine dioxygenase 2 (TET2) and DNA methyltransferase 3 alpha (DNMT3A) in AML and myelodysplastic syndrome lead to either hypermethylation or hypomethylation of enhancers, thereby affecting the accessibility of specific TFBS. The gene discussed is DNMT3A; the disease is myelodysplastic syndrome.