For example, anemias, characterized by reduced hemoglobin concentration (Hb) and altered red blood cell (RBC) numbers, can be both a disease and a feature of other conditions such as myelodysplastic syndromes (MDS), a heterogeneous group of myeloid neoplasms that can progress to acute myeloid leukemia (AML)2–4. The gene discussed is GSTM1; the disease is myelodysplastic syndrome.