Muscle phenotype in patients with myotonic dystrophy type 11. Issue 3 (21st November 2012)

• Record Type: Journal Article
• Authors: Andersen, Grete; Ørngreen, Mette C.; Preisler, Nicolai; Colding‐J⊘rgensen, Eskild; Clausen, Torben; Duno, Morten; Jeppesen, Tina D.; Vissing, John
• Is Part Of: Muscle & nerve. Volume 47:Issue 3(2013:Mar.)
• Page Start: 409
• Page End: 415
• Publication Date: 2012-11-21
• Subjects: Neuromuscular diseases -- Periodicals; Muscles -- Periodicals; Nerves -- Periodicals; 616.74
• DOI: 10.1002/mus.23535
• Languages: English
• ISSNs: 0148-639X

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <p> <italic>Introduction</italic>: The pathogenesis of muscle involvement in patients with myotonic dystrophy type 1 (DM1) is not well understood. In this study, we characterized the muscle phenotype in patients with confirmed DM1. <italic>Methods</italic>: In 38 patients, muscle strength was tested by hand‐held dynamometry. Myotonia was evaluated by a handgrip test and by analyzing the decrement of the compound muscle action potential. Muscle biopsies were assessed for morphological changes and Na⁺‐K⁺ pump content. <italic>Results</italic>: Muscle strength correlated with a decline in Na⁺‐K⁺ pump content (<italic>r</italic> = 0.60, <italic>P</italic> &lt; 0.001) and with CTG expansion. CTG expansion did not correlate with severity of myotonia, proximal histopathological changes, or Na⁺‐K⁺ pump content. Histopathologically, we found few centrally placed nuclei (range 0.2–6.9%). <italic>Conclusions</italic>: The main findings of this study are that muscle weakness correlated inversely with CTG expansion and that central nuclei are not a prominent feature of proximal muscles in DM1. <italic>Muscle Nerve</italic> 47:409‐415, 2013</p> </abstract>