GSTM1 and Schnyder corneal dystrophy: Several naturally occurring Hb variants have been implicated in SCD pathologies [4,5,6,7,8,9,10], with the most well-known variant sickle Hb (HbS), resulting from a single-nucleotide mutation in the β-globin gene that codes for βVal6 instead of βGlu6 [7,8].