WHO5 includes a mutation‐based definition of AML, myelodysplasia‐related (AML‐MR) group, based on a set of eight genes—SRSF2, SF3B1, U2AF1, ZRSR2, ASXL1, EZH2, BCOR, and STAG2 [1]. The gene discussed is BCOR; the disease is acute myeloid leukemia.