A 5-month-old infant presents with progressive generalized hypotonia, macroglossia, severe concentric cardiac hypertrophy, and cardiomegaly on echocardiography. Muscle biopsy shows vacuoles filled with PAS-positive material, and acid alpha-glucosidase activity in leukocytes is markedly reduced. What is the diagnosis?
- A Danon disease
- B Pompe disease (glycogen storage disease type II) ✓
- C Glycogen storage disease type IV (Andersen disease)
- D Duchenne muscular dystrophy
Correct answer: B. Pompe disease (glycogen storage disease type II)
Explanation
Pompe disease is caused by deficiency of lysosomal acid alpha-glucosidase (acid maltase), producing glycogen accumulation inside lysosomes. The infantile form presents with cardiomegaly, hypotonia, and macroglossia, and death usually results from cardiac failure. Danon disease is an LAMP2 cardiomyopathy without enzyme deficiency, Andersen disease involves branching enzyme with cirrhosis, and dystrophinopathies do not show lysosomal glycogen-filled vacuoles.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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