GP6 and immune system disorder: Thus, Btk might be a promising therapeutic target of platelet-related diseases, and BTKi have indeed been proposed as novel antiplatelet drugs as they inhibit selectively platelet GPVI/GPIb-stimulated atherothrombosis (7, 8), platelet FcγRIIA-dependent immune disorders (heparin-induced thrombocytopenia, vaccine-induced immune thrombotic thrombocytopenia) (9, 10), and podoplanin/CLEC-2 mediated venous thrombosis (11, 12).