Neuropediatrics 1983; 14(1): 47-52
DOI: 10.1055/s-2008-1059552
CASE REPORTS

© Georg Thieme Verlag KG Stuttgart · New York

Fetal Muscle Characteristics in Nemaline Myopathy

I.  Nonaka1 , M.  Tojo1 , H.  Sugita2
  • 1Div. of Neuromuscular Research, National Center for Nervous, Mental and Muscular Disorders, Kodaira, Tokyo 187, Japan
  • 2Div. of Neuromuscular Research, National Center for Nervous, Mental and Muscular Disorders, Kodaira, Tokyo 187, Japan and Dept. of Neurology, Institute of Brain Research, University of Tokyo, Tokyo 113, Japan
Further Information

Publication History

Publication Date:
15 May 2008 (online)

Abstract

In addition to the intracytoplasmic rods in approximately 1/4 muscle fibers, there were a large number of fibers with fetal muscle characteristics in a female infant who had severe muscle weakness and hypotonia, and failure to thrive since birth. A histochemical examination disclosed abnormal distribution in muscle fiber types including remarkable type 1 fiber predominance and increased number of type 2C fibers (11.4 %). Scattered throughout were fibers consisting of multiple myocytes enclosed in a single basement membrane, and small-calibered fibers containing abundant intermediate (skeletin) filaments and dispersed microtubules. Both were histologically identical to premature fibers found in the fetal muscle. The existence of an increased number of satellite cells as compared with age-matched controls was also suggestive of delayed or arrested muscle fiber maturation. A certain impaired neural influence upon the developing muscle is probably responsible for producing abnormal fiber type distribution and immature small-calibered fibers which account for small muscle bulk and muscle weakness in nemaline myopathy.

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