SF3B1 and myelodysplastic syndrome: The splicing factor genes found to be mutated in MDS code for proteins that have a role in the recognition of 3′ splice sites during processing of pre-messenger RNAs.3 Altered RNA splicing has been suggested as the mechanism underlying the observed phenotypic changes concomitant to splicing factor gene mutations, including SF3B1, and the identification of aberrantly spliced target genes in the hematopoietic cells of SF3B1-mutant MDS cases is important.