The most common SCD genotype reported in this population was Hb SS, present in 77% of cases, followed by Hb Sβ0 in 9.9% and Hb Sβ+ in 7.2%, and HbSC in 3.5%, while the rest of the genotypes, including HbS/α-Thal, HbSD, HbSE, HbSO-Arab, HbSβ0 + Alpha Thal, and HBS-Oman were individually reported in <4% of the cases (N=520). The gene discussed is GSTM1; the disease is Schnyder corneal dystrophy.