U2AF1 and myelodysplastic syndrome: Mutations in other splicing genes, such as the U2 small nuclear RNA auxiliary factor 1 gene (U2AF1), the serine/arginine-rich splicing factor 2 gene (SRSF2), and the U2 small nuclear ribonucleoprotein auxiliary factor 35 kDa subunit-related protein 2 gene (ZRSR2), have also been reported; however, these are less frequent and not associated with ring sideroblasts in MDS patients [9,10].