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The pathology of type II skeletal muscle glycogenosis. A light and electron-microscopic study
Insights
Infants with Pompe disease show muscle vacuolar myopathy and material accumulation, similar to adults. This suggests acid maltase deficiency
Area of Science:
- Neuromuscular Disorders
- Metabolic Myopathies
- Pediatric Pathology
Background:
- Pompe disease, a lysosomal storage disorder caused by acid alpha-glucosidase deficiency, leads to glycogen accumulation.
- Muscle pathology in infantile Pompe disease typically involves vacuolar myopathy and PAS-positive material.
- The role of other accumulating substances and inflammatory responses in Pompe disease pathogenesis is less understood.
Purpose of the Study:
- To investigate the detailed muscle pathology in infants with Pompe disease.
- To compare infantile Pompe disease muscle findings with those in adult cases.
- To explore potential factors beyond glycogen storage contributing to muscle damage in acid maltase deficiency.
Main Methods:
- Muscle biopsies from three infants diagnosed with Pompe disease were analyzed.
- Histopathological examination included PAS staining and assessment for metachromatic material.
- Comparison with muscle biopsy data from two adult Pompe disease patients.
Main Results:
- Infant biopsies showed severe vacuolar myopathy with significant PAS-positive material.
- Abundant metachromatic material was present in all infant muscle fibers.
- Infants exhibited sparse perivascular lymphocytic infiltrates; adults showed denser infiltrates, particularly around vessels.
Conclusions:
- Muscle pathology in infantile Pompe disease shares features with adult cases, including vacuolar myopathy.
- The presence of metachromatic material and lymphocytic infiltrates suggests a broader pathogenic mechanism.
- Acid maltase deficiency-related muscle disorder may involve factors beyond abnormal glycogen storage.
Abstract:
Muscle biopsies were obtained from three infants under the age of 12 mth, each of whom was diagnosed as having Pompe's disease. The biopsies revealed a severe vacuolar myopathy with accumulation of large amounts of PAS positive material within the muscle fibres, changes similar to those in adult cases of the disease. In addition large amounts of metachromatic material were found within the muscle fibres in all three cases and in two of them scattered, rather sparse perivascular lymphocytic infiltrates were seen in the interstitial tissue. Review of material previously obtained from two adult cases showed no accumulation of metachromatic material in the older case and only moderate amounts in the younger. However, dense interstitial lymphocytic infiltrates were seen in the former, some concentrated around small vessels. These observations suggest that the pathogenesis of the muscle disorder in acid maltase deficiency may not depend on abnormal glycogen storage only.