An autoimmune disorder in which the number of circulating platelets is reduced due to their antibody-mediated destruction. ITP is a diagnosis of exclusion and is heterogeneous in origin. The disease is MONDO_0008558 (autoimmune thrombocytopenic purpura). Also known as: ITP, idiopathic thrombocytopenia, idiopathic thrombocytopenia purpura, idiopathic thrombocytopenic purpura, primary thrombocytopenic purpura, thrombocytopenic purpura, autoimmune.