In this analysis we considered 19 clinically asymptomatic SCD patients (age = 22.4 ± 7.8 years; Hb = 10.1 ± 2.1 g/dL; F = 9 patients), 15 non-SCD anemic patients (age = 22.4 ± 4.8 years; Hb = 10 ± 2.8 g/dL; F = 8 patients) and 23 control subjects (age = 21.3 ± 6 years; Hb = 13.3 ± 1.2 g/dL; F = 14 individuals). This evidence concerns the gene GSTM1 and Schnyder corneal dystrophy.