GP6 and stroke disorder: Mice lacking GPVI, either by genetic deficiency of the Gp6 gene or the FcRγ-chain or by antibody-mediated depletion from the platelet surface, display defective platelet responses to collagen but only a marginally impaired hemostasis, while they are profoundly protected from arterial thrombosis (53, 54) and experimental stroke (see Figure 1) (22).