Pompe disease is caused by deficiency of which enzyme?

• A. Lysosomal acid alpha-glucosidase
• B. Glucose-6-phosphatase
• C. Glycogen debranching enzyme
• D. Glycogen phosphorylase

Answer: (A)

The key concept is that Pompe disease results from a deficiency of a lysosomal enzyme that digests glycogen. Specifically, lysosomal acid alpha-glucosidase (acid maltase) is missing or deficient, so glycogen cannot be broken down inside lysosomes. This leads to accumulation of glycogen within lysosomes, especially in heart and skeletal muscle, causing early-onset cardiomyopathy and progressive muscle weakness.

The other enzymes listed work in the cytosol to mobilize glycogen, not inside lysosomes, so their deficiencies produce different glycogen storage diseases with distinct clinical features (for example, issues related to hypoglycemia or muscle/branching enzyme problems) rather than the prominent lysosomal glycogen buildup seen in Pompe disease.