Sphingolipidoses: Niemann-Pick disease: practice question

The best answer is B, Acid sphingomyelinase, with accumulation of sphingomyelin. Niemann-Pick disease types A and B result from acid sphingomyelinase deficiency, so sphingomyelin accumulates in lysosomes of macrophages and neurons.

Galactocerebrosidase deficiency causes Krabbe disease with globoid cells, irritability and spasticity, not organomegaly.

Alpha-galactosidase A deficiency causes Fabry disease, which presents in later childhood with pain and angiokeratomas.

Hexosaminidase A deficiency causes Tay-Sachs disease, which has a cherry-red spot but no hepatosplenomegaly.

It tests Sphingolipidoses: Niemann-Pick disease in Biochemistry. Hepatosplenomegaly with a cherry-red spot and neurodegeneration in infancy distinguishes type A from Tay-Sachs disease, in which organomegaly is absent.

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.

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.

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.