For some patients, 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.