The following are the SCD genotypes: hemoglobin sickle C (HbSC) disease, double heterozygote for HbS and hemoglobin C (HbC) with intermediate clinical severity; HbS/hereditary persistence of fetal Hb (S/HPHP), extremely mild phenotypic or symptom-free; HbSS disease, often known as SCA, homozygote for the Bs globin with a severe or moderately severe phenotype; and HbS/HbE syndrome, a fairly uncommon condition with a generally mild clinical history that is a double heterozygote for HbS and HbE [8]. This evidence concerns the gene GSTM1 and Schnyder corneal dystrophy.