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Can Med Assoc J. 1963 November 9; 89(19): 983–986.
PMCID: PMC1921896

Light and Electron Microscopic Studies of “Myogranules” in a Child with Hypotonia and Muscle Weakness


Examination by light and electron microscopy of more than 100 muscle biopsies revealed one very unusual case. A 4-year-old boy with non-progressive muscle weakness and hypotonia was found to have small particles, termed “myogranules”, in many muscle fibres from two gastrocnemius biopsies. Paraffin sections and thin sections of plastic-embedded muscle showed that the rod-shaped myogranules measured between 0.1 and 5 microns in length, and were usually orientated in the long axis of the fibre. Normal cross-striations could not be seen in areas occupied by myogranules, although adjacent parts of the same fibre were normal. Electron micrographs showed myofilaments running through the myogranules and a periodicity similar to sections of recrystallized muscle protein paramyosin. It is possible that this child has a disturbance of muscle proteins.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • PAINE RS. The future of the 'floppy infant': a follow-up study of 133 patients. Dev Med Child Neurol. 1963 Apr;5:115–124. [PubMed]
  • MULDAL S, OCKEY CH. Deletion of Y chromosome in a family with muscular dystrophy and hypospadias. Br Med J. 1962 Feb 3;1(5274):291–294. [PMC free article] [PubMed]

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