Progressive depletion of fast alpha-actinin-positive muscle fibers in Duchenne muscular dystrophy.
In normal human muscle, a monoclonal antibody against alpha-actinin recognizes an isoform that is only expressed in a population of fast fibers histochemically identified as type IIb or fast-twitch glycolytic. Immunohistochemical studies of muscle biopsies from patients with Duchenne muscular dystrophy (DMD) showed that the number of alpha-actinin-positive type IIb fibers was essentially normal in preclinical patients. Symptomatic patients between the ages of 3 and 5 years showed depletion of these fibers, which were not seen in patients older than 5 years. ATPase histochemistry showed that a few type IIb fibers were present in muscle from symptomatic DMD patients but lacked the fast isoform of alpha-actinin. The data suggest that type IIb fibers are affected early in DMD.
Minetti
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C
Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY.
Ricci
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Bonilla
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E
D000185:Actinin / Q000378:metabolism*; D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005455:Fluorescent Antibody Technique; D006801:Humans; D007223:Infant; D008297:Male; D009132:Muscles / Q000378:metabolism*; D009136:Muscular Dystrophies / Q000378:metabolism*
D000185:Actinin