Macrothrombocytopenia with mitral valve insufficiency is a rare hemorrhagic disorder due to a platelet anomaly characterized by dysfunctional platelets of abnormally large size, moderate thrombocytopenia, prolonged bleeding time and mild bleeding diathesis (ecchymoses and epistaxis), associated with mitral valve insufficiency. The disease is marcothrombocytopenia with mitral valve insufficiency (MONDO_0016360).