A defect in which the aorta and pulmonary artery do not form separately. Instead, a large artery, called the truncus, comes from the heart. As the truncus leaves the heart, it may branch into arteries that carry blood to the body and to the lungs. Symptoms Blue tint to the skin (cyanosis) Fatigue Rapid breathing Shortness of breath Clubbed fingers/toes Treatment Surgery is required to correct the defect.