ITGB3 and Glanzmann thrombasthenia 1: In 1982, Van Leeuwen et al. found that antibodies from patients with ITP bound to normal platelets, but not to platelets from patients with Glanzmann’s thrombasthenia; thus, he speculated that patients with ITP produced autoantibodies against platelet glycoprotein (GP) IIb or GPIIIa since patients with thrombasthenia lack either of these proteins [22].