Because of the high frequency of SF3B1 mutations in MDS/MPN-RS-T and the correlation between SF3B1 mutation and bone marrow RS, in the 2022 WHO classification, people with SF3B1 mutation and <15% bone marrow RS were reclassified as myelodysplastic/myeloproliferative neoplasms with SF3B1 mutation and thrombocytosis (MDS/MPN-SF3B1-T) [15–19]. The gene discussed is SF3B1; the disease is myelodysplastic syndrome.