Acid maltase deficiency

Definition

Enzyme deficiency of alpha glucosidase found in lysosomes that catalyze glucose release from complex sugars. Located on chromosome 7q21-23, alpha-glucosidase deficiency is thought to be transmitted as an autosomal recessive trait that affects three distinct age groups. Infant form, Pompe's disease, occurs between 0–2 years of age causing weakness, hypotonia, and CHF invariably leading to death. Massive gloycogen deposits can be found in cardiac, hepatic, neural and muscular tissue. Early childhood forms present with muscle weakness, proximal > distal, with progressive respiratory failure leading to death in the 30s. May simulate Duchenne's muscular dystrophy with firm, rubbery gastrocnemius and deltoid muscles, gastrocnemius hypertrophy and the Gowers' sign. Late toe walking develops after ankle contractures and lumbar lordosis creates an unsteady gait.

Adult onset, 30–40s, with muscle weakness noted to be a progressive myopathy, one third develop respiratory compromise....