The patient’s laboratory findings when he was 8 months old were as follows: microcytic anemia without other laboratory abnormalities, with Hb 6.2 g/dL, hematocrit (Hct) 20 %, mean corpuscular volume (MCV) 74.40 fL, mean corpuscular hemoglobin (MCH) 22.90 pg, without iron deficiency. The gene discussed is GSTM1; the disease is anemia (phenotype).