The course of SCD is partly distinguished by type: hemoglobin Hb S/S and Hb S/β0 are typically more severe, though novel SCD therapies are extending patient lifespan [10], while Hb S/C, Hb S/β+ and other Hb S sub-types typically are milder [2]. Here, GSTM1 is linked to Schnyder corneal dystrophy.