H2BC21 and coronary artery disorder: Rnf20 and Rnf40 encode subunits of a H2B ubiquitin ligase, and CHD patients were enriched for de novo mutations in genes in this H2B monoubiquitination pathway, including RNF20 and UBE2B, an E2 ubiquitin-conjugating enzyme involved in writing H2Bub116,17.