Question

Glycogen storage disease which presents as a lysosomal storage disease is:

• A. Von Gierke's disease
• B. Pompe's disease
• C. McArdle's disease
• D. Andersen's disease

Hint:

Look for the glycogenosis caused by a lysosomal acid maltase defect.

Answer 1

The Correct Option is B

Step 1: Frame the question by enzyme location. Most glycogen storage diseases involve cytosolic enzymes of glycogen synthesis or breakdown. Only one involves an enzyme that works inside the lysosome, and that single exception is what the question asks for.

Step 2: The enzyme acid maltase (acid alpha-glucosidase) lives in lysosomes and degrades glycogen there. When it is deficient, glycogen piles up inside lysosomes, producing type II disease known as Pompe's disease. This dual identity, both a glycogen storage disorder and a lysosomal storage disorder, is the key teaching point.

Step 3: Rule out the rest. Von Gierke (type I, glucose-6-phosphatase), McArdle (type V, muscle phosphorylase) and Andersen (type IV, branching enzyme) all stem from non-lysosomal enzyme defects and so do not fit.

\[\boxed{\text{Pompe's disease}}\]