Somatic mutations in myelodysplastic syndrome with ring sideroblasts and chronic lymphocytic leukaemia.

SF3B1 is the largest subunit of the Spliceosome Factor 3b (SF3B) complex and part of the U2 small nuclear ribosomal protein. It functions as an important part of spliceosomal assembly, converting precursor messenger RNA (mRNA) to mRNA ready for ribosomal translation. Mutations of are commonly seen in myelodysplastic syndromes with ring sideroblasts (MDS-RS)and MDS/myeloproliferative neoplasm (MPN-RS-T). These mutations are typically heterozygous missense substitutions, of which, 55% involve K700E. MDS-RS and MDS/MPN-RS-T usually carry a more favourable prognosis than other subtypes of MDS. itself does not influence survival in these conditions, but does correlate with increased thrombotic risk. Mutated is present in 9%-15% of chronic lymphocytic leukaemia cases and on its own correlates with improved responsiveness to ibrutinib, but is associated with additional adverse genetic abnormalities including and mutations, which traditionally confer adverse outcomes.