A Pilot Study of Pyridostigmine in Pompe Disease

Pompe is a rare disease, which occurs in approximately 1 per 40,000 births. It is a progressive and often fatal neuromuscular disorder resulting from mutation in the gene for acid alpha-glucosidase (GAA), an enzyme necessary to degrade glycogen. Accumulation of glycogen in multiple tissues results in cardiac, respiratory and skeletal muscle dysfunction. Enzyme replacement therapy (ERT) is currently the only treatment available, and although it prolongs survival, adjuvant therapies are needed to help alleviate the dire symptoms of Pompe disease. Recent data has revealed that degradation of the neuromuscular junction (NMJ) occurs in Pompe disease. Acetylcholinesterase inhibitors (AChEI) are substances that inhibit the AChE enzyme from degrading acetylcholine at the NMJ, and thus increase the functional impact of this neurotransmitter. AChEI are established as a beneficial therapy for individuals with primary diseases of the NMJ, such as myasthenia gravis. Recently, administration of an AChEI was demonstrated to improve NMJ pathology in both mice and individuals affected by other congenital myopathies, including autosomal centronuclear myopathies (CNM), X-linked myotubular myopathy (XLMTM) and mutation of tropomyosin 3 (TPM3). Specifically, both NMJ transmission and motor function were improved. These studies demonstrate that AChEI can be beneficial in myopathy associated with NMJ pathology. In this study, we will study the acute effects of pyridostigmine on neuromuscular transmission, as well as the prolonged effects on respiratory function, skeletal muscle function and quality of life over a 90 day treatment period. This project focuses on developing an adjuvant treatment to ERT that targets dysfunction at the NMJ. Our ultimate goal is to reduce the deleterious consequences of Pompe disease and improve the overall quality and duration of life in affected individuals.