Myocardial ischemia due to coronary artery disease is an extremely rare condition in childhood and adolescence. Absence of obvious serious risk factors remains a challenge to modern cardiology. We present the case of a 14-year-old boy who underwent quadruple-vessel coronary artery bypass grafting with bilateral pedicled internal mammary artery and bilateral radial artery grafting. We try to highlight a rare but important 4G variant PAI-1 (SERPINE 1) gene mutation as the etiology of severe coronary artery disease in our patient. To the best of our knowledge, he is one of the youngest patients who underwent coronary artery bypass surgery with 4 arterial grafts.