U2 small nuclear RNA auxiliary factor 1 ( U2AF1 ) is one of the most frequently mutated genes in myelodysplastic neoplasms (MDS) 1 , 2 . U2AF1 mutations predominantly occur at two hotspots (S34, Q157) within two zinc finger domains and disrupt pre-mRNA splicing by altering RNA binding specificity, with S34 and Q157 variants affecting nucleotide recognition at the −3 and +1 positions of the 3′ splice site, respectively 2 , 3 , 4 . Emerging evidence suggests that mutations at these residues induce distinct alterations in downstream gene expression and RNA splicing, and are associated with distinct disease phenotypes 3 , 5 , 6 , 7 , 8 , 9 . However, their prognostic impact in MDS remains inconclusive 6 , 7 , 8 , 9 , 10 , 11 , and potential differences among the specific amino acid substitutions within each hotspot have not been well defined.
Bao et al. (Fri,) studied this question.