Effects of enzyme replacement therapy on bone density in late onset Pompe disease.

Pompe disease is an autosomal recessive disorder caused by a deficiency of α-glucosidase, resulting in the accumulation of glycogen in smooth, cardiac, and skeletal muscles, leading to skeletal muscle dysfunction, proximal muscle weakness, and early respiratory insufficiency. Although many patients exhibit decreased bone mineral density (BMD) and increased fractures, there is currently no official protocol for surveillance and management of osteoporosis and osteopenia in late onset Pompe disease (LOPD). Enzyme replacement therapy (ERT) has therapeutic effects on muscle function; however, very few studies report on the effect of ERT on bone mineralization in LOPD patients. Our study included 15 Pompe patients from 25 to 76 years of age on ERT for variable durations. Progressive impact of ERT on BMD of the hips and spine, and the frequency of osteopenia or osteoporosis was studied using DEXA scanning, and correlations were made with age of initiation of ERT, duration of ERT and six-minute walk test. We found a significant positive correlation between the age of ERT initiation and age of the subject, with increases in the Z-scores for the femur and lumbar region. Females had a significantly higher risk for developing osteoporosis compared to males. These results highlight the significance of ERT on reducing progression of osteoporosis in LOPD patients.

Safety and effectiveness of resistance training in patients with late onset Pompe disease - a pilot study.

Pompe disease is a progressive myopathy resulting from deficiency in lysosomal enzyme acid α-glucosidase (GAA), which leads to glycogen accumulation in lysosomes primarily in skeletal and cardiac muscle. Enzyme replacement therapy (ERT) with recombinant human (rh) GAA works well in alleviating the cardiomyopathy; however, many patients continue to have progressive muscle weakness. The purpose of this study was to evaluate the effectiveness of a respiratory training combined with 24-week supervised resistance training program on muscle strength (measured by Biodex)), and respiratory function including maximum inspiratory pressure (MIP), maximum expiratory pressure (MEP) in subjects with late onset Pompe disease receiving ERT. Ten subjects participated in a 24-week resistance exercise program, three times per week, in addition to respiratory muscle exercise training six days per week. Overall, at the end of the resistance training program, as measured by Biodex dynamometry, the leg extensor strength improved by 10.5 ±â€¯3.2Nm. (