SELP and Schnyder corneal dystrophy: The decrease in NO bioavailability could also be responsible for the enhanced platelet activation (13) observed in SCD patients, as documented by increased expression of platelet activation markers, such as P-selectin, CD63, activated glycoprotein IIb/IIIa, plasma soluble factor-3 and factor-4, β-thromboglobulin, and platelet-derived soluble CD40 ligand (21, 22).