SF3B1 and myelodysplastic syndrome: SF3B1 gene is often a target for somatic mutations preferentially occurring in 4 consecutive HEAT (Huntington elongation factor 3 protein phosphatase 2A and the yeast PI3-kinase TOR1) domains of the C-terminal region, with the lysine to glutamic acid substitution at codon 700 (K700E) reported in the majority of cases with MDS and ringed sideroblasts (MDS-RS), a subtype of MDS identified as low-risk.