Heparin-induced thrombocytopenia (HIT) is a relatively rare immune-mediated adverse reaction of heparin indicating by low platelet counts, as a result of anti-heparin-platelet factor 4 (PF4) antibodies, and arterial and venous thrombosis in almost 50–70% of patients with HIT (310). The gene discussed is PF4; the disease is Venous thrombosis.