A 29-year-old man has had angina for the past year. There is a family history of cardiovascular disease. On examination, his blood pressure is 120/80 mm Hg. Laboratory studies show total serum cholesterol 185 mg/dL and glucose 85 mg/dL. A mutation involving a gene encoding for which of the following is most likely present in this man's family?

Lipoprotein(a) is an altered form of LDL cholesterol that has the apolipoprotein B-100 portion of LDL linked to apolipoprotein A, and an increase in Lp(a) is independently associated with a risk for endothelial dysfunction and atherogenesis. Apolipoprotein E promotes the metabolism and clearance of LDL. Drugs such as statins that affect LDL receptor activity do not affect Lp(a) concentration. Early in the course of atheroma formation, angiotensin and its receptor may play a role in the development of hypertension, which then becomes a risk factor for atherosclerosis. Endothelin is a vasoconstrictor with no known role in atherogenesis. Decreased factor VIII leads to abnormal bleeding. Von Willebrand factor is required for normal platelet adhesion to collagen, and its absence leads to abnormal bleeding.