The del(5q) group of MDS with isolated 5q abnormality is usually characterized at the level of hematological phenotype by low bone marrow blast cell counts and lowered Hb levels (lower than in the rest of MDSs) and with increased or normal platelet levels (higher than in the rest of MDS); these MDSs are predominantly observed in females (75% of cases) and are associated with a favorable OS compared to the rest of MDS [5]. The gene discussed is GSTM1; the disease is myelodysplastic syndrome.