Acid Maltase Deficiency (Pompe Disease)

KEY FEATURES

• Glycogen storage disease due to pathogenic variant in the gene encoding acid alfa-1,4-glucosidase

• Age at presentation ranges from infancy to the late fifties and depends on the degree of residual enzyme activity

CLINICAL FINDINGS

• Juvenile and adult-onset forms present with slowly progressive proximal muscle weakness that includes respiratory failure

• Cardiomyopathy less common in the adult form

• Mildly elevated serum creatine kinase

• Muscle biopsy shows glycogen containing lysosomal vacuoles

DIAGNOSIS

• Suggested by detecting reduced acid-1,4-alfa-glucosidase activity on a dried blood spot

• Confirmed by genetic testing

TREATMENT

• Recombinant alfa-glucosidase (20 mg/kg intravenously every 2 weeks) or avalglucosidase alfa (20–40 mg/kg intravenously every 2 weeks) stabilizes disease progression and results in improvement in respiratory function