SCD genotypes include the homozygous mutation HbSS (sickle cell anemia, most common and severe type), and the compound heterozygous mutations such as HbSC (HbS and HbC), HbS-\begin{document}&beta;\end{document} thalassemia, HbSO Arabia, Hb-SE, HbSD Punjab / Los Angeles, and HbS-\begin{document}&alpha;\end{document} thalassemia [1]. Sickle cell trait (SCT), or carrier status, is not considered a form of SCD. This evidence concerns the gene GSTM1 and Schnyder corneal dystrophy.