Type 2 heparin-induced thrombocytopenia (HIT) is an immune-mediated, prothrombotic disorder driven by IgG antibodies against platelet factor 4 (PF4)/heparin complexes, leading to thrombocytopenia and platelet activation via FcγRIIa receptors, resulting in a hypercoagulable state. The gene discussed is PF4; the disease is Thrombocytopenia.