This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
[{'content': 'A person is diagnosed to have familial type IIa hyperlipoproteinemia. What is the basic defect in this type of hyperlipoproteinemia? \nSelect and explain. \nA. Lipoprotein lipase deficiency, B. Defective LDL receptor, C. Abnormal activity of Apo E, D. Overproduction of LDL', 'role': 'user'}, {'content': "Answer: B \nExplanation: Familial type IIa hypercholesterolemia is associated with a defect in the LDL receptor or with a mutation in ligand region of apo B-100. These patients have elevated levels of cholesterol and LDL which in turn result in atherosclerosis and coronary hea disease. Type I hyperlipoproteinemias is associated with lipoprotein lipase deficiency or apo C II deficiency causing inactive LPL. Type III hyperlipoproteinemias is due to abnormality in apo E. Type IV hyperlipoproteinemias is due to overproduction of VLDL. Ref: Botham K.M., Mayes P.A. (2011). Chapter 26. Cholesterol Synthesis, Transpo, & Excretion. In D.A. Bender, K.M. Botham, P.A. Weil, P.J. Kennelly, R.K. Murray, V.W. Rodwell (Eds), Harper's Illustrated Biochemistry, 29e.", 'role': 'assistant'}]