Inherited conditions that affect clotting are:Factor V Leiden thrombophiliaProthrombin G20210A mutationOther rare conditions such as protein C, protein Santithrombin III deficiencies, and A blood clot may block an artery or vein in the heart, affecting the:Heart (angina or a heart attack)Intestines (mesenteric ischemiamesenteric venous thrombosis) or Kidneys (renal vein thrombosis)Leg or arm arter