SF3B1 is the most common somatic spliceosome machinery gene mutation in adult MDS [4,45,46] and is associated with a highly homogenous phenotype characterized by erythroid dysplasia, ring sideroblasts, ineffective erythropoiesis, and often normal or nearly normal platelet and neutrophil counts [46,47,48]. This evidence concerns the gene SF3B1 and myelodysplastic syndrome.