Mucolipidosis II (I-cell disease): studies of muscle biopsy and muscle cultures.
Muscle cultures from a patient with I-cell disease showed the characteristic morphologic and biochemical abnormalities previously observed in cultured fibroblasts. At early stages of myoblast growth, there were numerous inclusions. Biochemically, the intracellular activities of beta-galactosidase, beta-hexosaminidase, and alpha-mannosidase were reduced to 1, 14, and 5%, respectively, of control values, and this was accompanied by elevated levels of beta-hexosaminidase and alpha-mannosidase in the culture medium. Cultures from the patient did not fuse as well as controls; however, when well-developed myotubes possessing distinct cross-striations were present, these no longer had inclusions. In the muscle biopsy from this patient, only beta-galactosidase was decreased to approximately 50% of the mean control value whereas beta-hexosaminidase and alpha-mannosidase activities were increased as compared to controls. These data suggest that the I-cell mutation is expressed during early myogenesis but not in well-differentiated myotubes or mature muscle fibers.
D001706:Biopsy; D002478:Cells, Cultured; D002675:Child, Preschool; D003402:Creatine Kinase / Q000378:metabolism; D005260:Female; D006596:Hexosaminidases / Q000378:metabolism; D006651:Histocytochemistry; D006801:Humans; D007527:Isoenzymes; D008361:Mannosidases / Q000378:metabolism; D009081:Mucolipidoses / Q000201:enzymology / Q000473:pathology*; D009132:Muscles / Q000201:enzymology / Q000473:pathology*; D000520:alpha-Glucosidases / Q000378:metabolism; D043323:alpha-Mannosidase; D001616:beta-Galactosidase / Q000378:metabolism; D001619:beta-N-Acetylhexosaminidases
D007527:Isoenzymes; D003402:Creatine Kinase; D006596:Hexosaminidases; D008361:Mannosidases; D000520:alpha-Glucosidases; D001616:beta-Galactosidase; D043323:alpha-Mannosidase; D001619:beta-N-Acetylhexosaminidases