Laboratory investigations reported pancytopenia with a hemoglobin (Hb) level of 8.7 g/dL, a hematocrit of 25.3%, a white blood cell (WBC) count of 3040 cells/mm3 (neutrophil, 55%; lymphocyte, 33%; monocyte, 11%; atypical lymphocyte, 1%), and a platelet count of 63,000 platelets/mm3. The gene discussed is GSTM1; the disease is Pancytopenia.