Genetic and metabolic disorders: homozygous familial hypercholesterolaemia: practice question

A Pediatrics 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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Pediatrics · Genetic and metabolic disorders: homozygous familial hypercholesterolaemia

Sample item

A 6-year-old has yellow planar xanthomas over the hands and buttocks and tendon xanthomas. Total cholesterol is 700 mg/dL, and both parents have moderately raised cholesterol. Which defect is responsible?

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

The answer and the reasoning

C. Defective LDL receptor function

Homozygous familial hypercholesterolaemia results from absent LDL receptor function, causing very high LDL cholesterol, early xanthomas and premature coronary disease. Heterozygous parents have moderately raised cholesterol. Treatment includes statins, ezetimibe and LDL apheresis.

Option by option

  • A. Lipoprotein lipase deficiency

    Lipoprotein lipase deficiency causes chylomicronaemia with eruptive xanthomas, abdominal pain and pancreatitis, with normal LDL.

  • B. Lecithin-cholesterol acyltransferase deficiency

    Lecithin-cholesterol acyltransferase deficiency causes low HDL with corneal opacities and haemolytic anaemia.

  • C. Defective LDL receptor function (correct)

    Correct. Absent LDL receptor function gives very high LDL and early xanthomas, with heterozygous parents.

  • D. Apolipoprotein A-I deficiency

    Apolipoprotein A-I deficiency lowers HDL and does not produce this extreme LDL elevation.

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 Pediatrics question

What is the answer to this Pediatrics question?

The best answer is C, Defective LDL receptor function. Homozygous familial hypercholesterolaemia results from absent LDL receptor function, causing very high LDL cholesterol, early xanthomas and premature coronary disease.

Why is "Lipoprotein lipase deficiency" not the answer?

Lipoprotein lipase deficiency causes chylomicronaemia with eruptive xanthomas, abdominal pain and pancreatitis, with normal LDL.

Why is "Lecithin-cholesterol acyltransferase deficiency" not the answer?

Lecithin-cholesterol acyltransferase deficiency causes low HDL with corneal opacities and haemolytic anaemia.

Why is "Apolipoprotein A-I deficiency" not the answer?

Apolipoprotein A-I deficiency lowers HDL and does not produce this extreme LDL elevation.

What concept does this question test?

It tests Genetic and metabolic disorders: homozygous familial hypercholesterolaemia in Pediatrics. Heterozygous parents have moderately raised cholesterol. Treatment includes statins, ezetimibe and LDL apheresis.

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 Genetic and metabolic disorders: homozygous familial hypercholesterolaemia?

Memorise milestones and the vaccine schedule as tables and revise them often. Then use the flashcards and the other Pediatrics 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.