SF3B1 and myelodysplastic syndrome: While the prevalence of SF3B1 mutation is 20–28% in the entire MDS population11, mutation frequencies in MDS with RS (MDS-RS) are higher, with 80% and 40% for MDS-RS with single lineage dysplasia (MDS-RS-SLD) and multilineage dysplasia (MDS-RS-MLD), respectively12.