Apart from KMT2A, three other CXXC-domain-containing epigenetic regulators have been linked to Mendelian diseases: KMT2B (DYS28; OMIM:617284), DNMT1 (HSN1E; OMIM:614116), and TET3 (BEFAHRS; OMIM:618798). This evidence concerns the gene KMT2B and hereditary disease.