Both KMT2D and KDM6A act as epigenetic regulators via histone modifications,[39] and small-molecule inhibitors of histone deacetylases can be used for the treatment of intellectual disability and can reduce the risk of cancer in KS.[40] We report a case of neonatal KS caused by heterozygous gene mutation in KMT2D;NM_003482.3:c.755dupA(p.His252Glnfs*21). The gene discussed is KMT2D; the disease is cancer.