A 19-year-old man suddenly collapses and is brought to the emergency department. His vital signs are temperature, 37.1C; pulse, 84/min; respirations, 18/min; and blood pressure, 80/40 mm Hg. Laboratory findings include hemoglobin, 13.5 g/dL; platelet count, 252,000/mm; WBC count, 7230/mm; serum glucose, 73 mg/dL; and creatinine, 1.2 mg/dL. The total creatine kinase (CK) level is elevated, with a CK-MB fraction of 10%. Which of the following underlying conditions is most likely to be present in this patient? (A) Hereditary hemochromatosis (B) Marfan syndrome (C) Down syndrome (D) DiGeorge syndrome (E) Familial hypercholesterolemia