Muscle weakness is the main symptom of Pompe disease, a lysosomal storage disorder for which major clinical benefits of enzyme replacement therapy (ERT) have been documented recently. Restoration of skeletal muscle function is a challenging goal. Type 2 muscle fibers of mice with Pompe disease have proven resistant to therapy. To investigate the response in humans, we studied muscle biopsies of a severely affected infant before and after 17 months of therapy. Type 1 and 2a fibers were marked with antibodies, and lysosome-associated membrane protein-1 (Lamp1) was used as the lysosomal membrane marker. Quantitative measurements showed a 2.5-3-fold increase of fiber cross-sectional area of both fiber types during therapy and normalization of the Lamp1 signal in ∼95% of type 1 and ∼75% of type 2a fibers. The response of both type 1 and 2a muscle fibers in the patient studied herein corroborates the beneficial effects of enzyme therapy seen in patients with Pompe disease.

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doi.org/10.1002/mus.20896, hdl.handle.net/1765/29435
Muscle & Nerve
Erasmus MC: University Medical Center Rotterdam

Drost, M., Schaart, G., van Dijk, P., van Capelle, C., van der Vusse, G., Delhaas, T., … Reuser, A. (2008). Both type 1 and type 2a muscle fibers can respond to enzyme therapy in Pompe disease. Muscle & Nerve, 37(2), 251–255. doi:10.1002/mus.20896