Background: Pompe's disease, a rare, inherited deficiency of the enzyme alpha-1,4-glucosidase (GAA), is a lysosomal storage disorder. Early-onset (infantile) Pompe's disease is associated with cardiomegaly and severe myopathy and, if left untreated, will inevitably lead to death within the first 2 years of life. In juvenile Pompe's disease, progression of the disease is generally slower and involvement of the myocardium is less likely with onset at a later age. The adult form of Pompe's disease is frequently associated with a progressive proximal myopathy which is more marked in the lower limbs. Involvement of the respiratory system is common. A new treatment with intravenous enzyme replacement (Myozyme) is now available. At present, there is only limited data available regarding its efficacy in the treatment of the adult form of Pompe's disease.
Case report: A 67-year-old lady with Pompe's disease and known severe respiratory compromise due to involvement of the respiratory muscles had had recurrent emergency admissions with respiratory failure. After only a few weeks of treatment with intravenous enzyme replacement with Myozyme, significant improvement in her respiratory function was noticed. Following a total length of treatment of 7 months, her arterial blood gas results on room air had almost returned to normal.
Conclusion: A glycogen storage disorder (type II) should be excluded in all adult patients with a slowly progressive weakness involving pelvic and thigh muscles even when respiratory involvement is not present. In addition to supportive treatment, a new enzyme replacement therapy for patients with late-onset disease has now become available which shows promising results.