The N-terminal globular domain of human platelet glycoprotein Ibα has a methionine 145/threonine 145 amino acid polymorphism which is associated with the HPA-2 (Ko) alloantigens - Kuijpers, R WAM; Faber, N M; Cuypers, H TM; von dem Borne, A EGK (J Clin Invest, 1992)