Lipoproteins: familial hypercholesterolemia: practice question

A Biochemistry question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Biochemistry · Lipoproteins: familial hypercholesterolemia

Sample item

A teenager has tendon xanthomas, very high LDL cholesterol, and early family history of myocardial infarction. Which defect is likely?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

A. LDL receptor dysfunction

Familial hypercholesterolemia commonly results from LDL-receptor dysfunction, leading to markedly elevated LDL, tendon xanthomas, and premature atherosclerosis. More severe homozygous disease presents earlier.

Option by option

  • A. LDL receptor dysfunction (correct)

    Correct. Impaired LDL clearance produces this phenotype.

  • B. Apo C-II deficiency

    Apo C-II deficiency does not primarily raise LDL.

  • C. Lipoprotein lipase deficiency

    LPL or Apo C-II deficiency causes severe hypertriglyceridemia and pancreatitis.

  • D. Abetalipoproteinemia

    Abetalipoproteinemia causes fat malabsorption and low apo B lipoproteins.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

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Questions about this Biochemistry question

What is the answer to this Biochemistry question?

The best answer is A, LDL receptor dysfunction. Familial hypercholesterolemia commonly results from LDL-receptor dysfunction, leading to markedly elevated LDL, tendon xanthomas, and premature atherosclerosis.

Why is "Apo C-II deficiency" not the answer?

Apo C-II deficiency does not primarily raise LDL.

Why is "Lipoprotein lipase deficiency" not the answer?

LPL or Apo C-II deficiency causes severe hypertriglyceridemia and pancreatitis.

Why is "Abetalipoproteinemia" not the answer?

Abetalipoproteinemia causes fat malabsorption and low apo B lipoproteins.

What concept does this question test?

It tests Lipoproteins: familial hypercholesterolemia in Biochemistry. More severe homozygous disease presents earlier.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Lipoproteins: familial hypercholesterolemia?

Build one table of enzyme deficiency, disease, inheritance and key finding, then revise it by spaced recall. Then use the flashcards and the other Biochemistry questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.