This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
Tetralogy of Fallot is a complex congenital heart defect characterized by a large ventricular septal defect (hole between the right and left ventricles), pulmonary stenosis (narrowing of the valve and artery that connect the heart with the lungs), an overriding aorta (the aorta – the artery that carries oxygen-rich blood to the body – is shifted over the right ventricle and ventricular septal defect, instead of coming out only from the left ventricle), and right ventricular hypertrophy (the muscle of the right ventricle is thicker than usual). Tetralogy of Fallot causes low oxygen levels in the blood, which can lead to cyanosis (a bluish-purple color to the skin). The cause of this condition is unknown. Treatment involves surgery to repair the heart defects. Sometimes more than one surgery is needed.
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