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 patient was diagnosed with an isolated increase in LDL. His father and brother had the same disease with increased cholesterol. The likely diagnosis is \nSelect and explain. \nA. Familial type III hyperlipoproteinemia, B. Abetalipoproteinemia, C. Familial lipoprotein lipase deficiency (type 1), D. LDL receptor mutation', 'role': 'user'}, {'content': 'Answer: D \nExplanation: LDL receptor mutation\xa0\n\nIsolated increase in LDL with positive family history suggests the diagnosis of familial hypercholesterolemia.\nFamilial hypercholesterolemia (type IIa) is due to deficiency of functional LDL receptors as a result of different types of mutations.', 'role': 'assistant'}]