There were temporary changes in white cell counts (4 episodes of leucopenia, 1 episode of leukocytosis), platelets (3 patients had mild thrombocytopenia), transient elevation in myelocytes and metamyelocytes (4, 5 patients), regular decreases in hemoglobin (Hb) and hematocrit (Hct), and expected rises in the mean corpuscular volume (MCV) while on dapsone due to the drug’s effect as a folic acid inhibitor, affecting bone marrow production [110]. The gene discussed is GSTM1; the disease is Increased total leukocyte count.