The Hb phenotypes of the patients with SCD consisted of 175 homozygous sickle cell disease (HbSS) (96.2%), five sickle-hemoglobin C disease (HbSC) (2.7%) and two sickle cell β-thalassemia (HbSβ) (1.1%). The gene discussed is GSTM1; the disease is Schnyder corneal dystrophy.