ZRSR2 is involved in splice-site selection, spliceosome assembly, and splicing.[30] Single mutation of ZRSR2 can usually be found in older patients which may lead to macrocytic anemia without dysplasia or other kinds of cytopenia.[46] A study showed a higher rate of AML transformation in a group of patients with ZRSR2 mutation in the IPSS-low/intermediate-1 subgroups.[27] The patients with ZRSR2 mutations exhibited higher blasts in bone marrow, and sometimes neutropenias. This evidence concerns the gene ZRSR2 and macrocytic anemia.