Markers of platelet activation such as a) increased expression of activation dependent antigens, P-selectin and glycoprotein IIbIIIa, on circulating platelets [3], [4], [5], b) increased plasma concentrations of platelet factor 4 [4], beta-thromboglobulin [4], thrombospondin-1 (TSP-1) [6], [7] and soluble CD40 ligand [8] and c) increased numbers of circulating platelet microparticles [3] have been detected in patients with SCD in steady state and are amplified during acute vaso-occlusive crisis [3]. This evidence concerns the gene THBS1 and Schnyder corneal dystrophy.