ICD9-CM: International Classification of Diseases, Ninth Revision, Clinical Modification; IHD: ischemic heart diseases; ASD: atrial septal disease; VSD: ventricular septal disease; PDA: patent ductus arteriosus; SLE: systemic lupus erythematosus; CNS: central nervous system; DM: diabetes mellitus; A-fib: atrial fibrillation; Hb SS: homozygous SCD patients; SC/HbC: sickle cell-hemoglobin C; SCD: sickle cell disease. The gene discussed is GSTM1; the disease is sickle cell disease.