Pompe disease is a rare neuromuscular disorder caused by an acid α-glucosidase (GAA) deficiency resulting in glycogen accumulation in muscle, leading to myopathy and respiratory weakness.
For example, glucose-6-phosphatase (G6Pase) deficiency in GSD type Ia (GSD Ia) affects primarily the liver and kidney, while acid α-glucosidase (GAA) deficiency in GSD II causes primarily muscle disease.
Glycogen storage disease type II is an autosomal recessive muscle disorder due to deficiency of lysosomal acid alpha-glucosidase and the resulting intralysosomal accumulation of glycogen.
Early initiation of enzyme replacement therapy (ERT) with recombinant human acid alpha-glucosidase is an effective treatment for patients with infantile-onset Pompe disease (IOPD) but cannot prevent a slow progression of myopathy.
Intercellular transfer of the virally derived precursor form of acid alpha-glucosidase corrects the enzyme deficiency in inherited cardioskeletal myopathy Pompe disease.
The screening of GSD2 through the measurement of acid alpha-glucosidase activity in dried blood spots was applied to a selected sample of 5 Mexican patients with proximal myopathies of unknown etiology.
Although many lysosomal disorders are corrected by a small amount of the missing enzyme, it has been generally accepted that 20-30% of normal acid alpha-glucosidase (GAA) activity, provided by gene or enzyme replacement therapy, would be required to reverse the myopathy and cardiomyopathy in Pompe disease.