Question

Accumulation of sphingomyelin in phagocytic cells is a feature of

• A. Gaucher's Disease
• B. Niemann-Pick Disease
• C. Tay-Sachs Disease
• D. Down's syndrome

Hint:

Sphingomyelinase deficiency causes sphingomyelin buildup, this is Niemann-Pick disease.

Answer 1

The Correct Option is B

Step 1: Recall what each storage disease accumulates.
Lysosomal storage diseases result from a missing or faulty enzyme, so a specific lipid builds up inside cells, mainly inside phagocytic cells such as macrophages.

Step 2: Identify the enzyme defect linked to sphingomyelin.
Niemann-Pick disease, types A and B, comes from a deficiency of the enzyme sphingomyelinase, which normally breaks down sphingomyelin. Without this enzyme, sphingomyelin builds up inside lysosomes of macrophages and other cells, these lipid filled macrophages are called foam cells.

Step 3: Rule out the other diseases.
Gaucher's disease is caused by a deficiency of glucocerebrosidase, and the stored lipid is glucocerebroside, not sphingomyelin, and its macrophages are called Gaucher cells, with a crumpled tissue paper appearance.
Tay-Sachs disease is caused by a deficiency of hexosaminidase A, and the stored lipid is GM2 ganglioside, mainly in neurons, not sphingomyelin.
Down's syndrome is a chromosomal disorder from trisomy 21, it is not a lysosomal storage disease and has no link to sphingomyelin accumulation.

Step 4: Final answer.
Accumulation of sphingomyelin in phagocytic cells is a feature of Niemann-Pick disease.
\[ \boxed{\text{Niemann-Pick Disease}} \]