Cell injury and adaptation: Tay-Sachs disease: practice question

A Pathology 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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Pathology · Cell injury and adaptation: Tay-Sachs disease

Sample item

A 7-month-old infant of Ashkenazi Jewish descent has lost the ability to sit, startles excessively to sound and has a cherry-red spot at the macula. The liver and spleen are not enlarged. Which material accumulates within the neuronal lysosomes?

ASphingomyelinBHeparan sulfateCGM2 gangliosideDGlucocerebroside

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

The answer and the reasoning

C. GM2 ganglioside

Hexosaminidase A deficiency blocks degradation of GM2 ganglioside, which builds up in neurons and gives onion-skin lysosomes on electron microscopy. The cherry-red macula appears because the pale ganglion cells around the fovea are packed with lipid. Absence of organomegaly separates it from Niemann-Pick disease.

Option by option

A. Sphingomyelin
Sphingomyelin accumulates in Niemann-Pick disease, which also causes hepatosplenomegaly.
B. Heparan sulfate
Heparan sulfate accumulates in mucopolysaccharidoses, with coarse facies and organomegaly.
C. GM2 ganglioside (correct)
Correct. GM2 ganglioside accumulates because hexosaminidase A is missing.
D. Glucocerebroside
Glucocerebroside accumulates in Gaucher disease, which has no cherry-red spot.

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.

Questions about this Pathology question

What is the answer to this Pathology question?

The best answer is C, GM2 ganglioside. Hexosaminidase A deficiency blocks degradation of GM2 ganglioside, which builds up in neurons and gives onion-skin lysosomes on electron microscopy.

Why is "Sphingomyelin" not the answer?

Sphingomyelin accumulates in Niemann-Pick disease, which also causes hepatosplenomegaly.

Why is "Heparan sulfate" not the answer?

Heparan sulfate accumulates in mucopolysaccharidoses, with coarse facies and organomegaly.

Why is "Glucocerebroside" not the answer?

Glucocerebroside accumulates in Gaucher disease, which has no cherry-red spot.

What concept does this question test?

It tests Cell injury and adaptation: Tay-Sachs disease in Pathology. The cherry-red macula appears because the pale ganglion cells around the fovea are packed with lipid. Absence of organomegaly separates it from Niemann-Pick disease.

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 Cell injury and adaptation: Tay-Sachs disease?

Learn each disease as a bundle: cause, key histology, markers, and the clinical hallmark. Then use the flashcards and the other Pathology 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.