Whole-exome sequencing (WES) of CD34+ cells from a cohort of 12 MDS-RS (8 RARS, 1 RCMD-RS, 2 RARS-T and 1 tMDS; Supplementary Table 1) including 8 previously reported4 and 1 congenital sideroblastic anaemia patient, revealed acquired mutations in SF3B1 in 11/13 cases (Supplementary Tables 1 and 2, Supplementary Fig. 1). Here, SF3B1 is linked to myelodysplastic syndrome.