title: Muscle pathology in 57 patients with myotonic dystrophy type 2.
abstract: We evaluated muscle biopsies from 57 patients with genetically confirmed myotonic dystrophy type 2/proximal myotonic myopathy (DM2/PROMM). Light microscopy showed myopathic together with "denervation-like" changes in almost all biopsies obtained from four different muscles: increased fiber size variation, internal nuclei, small angulated fibers, pyknotic nuclear clumps, and predominant type 2 fiber atrophy. Quantitative morphometry in 18 biopsies that were immunostained for myosin heavy chain confirmed a predominance of nonselective type 2 fiber atrophy. These histological changes were similar in all patients regardless of the site of biopsy, the predominant clinical symptoms and signs, and the clinical course. It is likely that, in a number of undiagnosed patients, DM2 is the underlying disorder. With a better understanding of the histopathological pattern in DM2, biopsies from patients with undiagnosed neuromuscular disorders can now be reevaluated.
authors.affiliation: Department of Neurology, Friedrich Baur Institute, Ludwig Maximilians University of Munich, Ziemssenstr. 1a, D-80336 Munich, Germany. bschoser@fbs.med.uni-muenchen.de
authors.forename: Benedikt G H
authors.initials: BG
authors.lastname: Schoser
authors.forename: Christiane
authors.initials: C
authors.lastname: Schneider-Gold
authors.forename: Wolfram
authors.initials: W
authors.lastname: Kress
authors.forename: Hans-Hilmar
authors.initials: HH
authors.lastname: Goebel
authors.forename: Peter
authors.initials: P
authors.lastname: Reilich
authors.forename: Manuela C
authors.initials: MC
authors.lastname: Koch
authors.forename: Dieter E
authors.initials: DE
authors.lastname: Pongratz
authors.forename: Klaus V
authors.initials: KV
authors.lastname: Toyka
authors.forename: Hanns
authors.initials: H
authors.lastname: Lochmüller
authors.forename: Kenneth
authors.initials: K
authors.lastname: Ricker
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000473:pathology*; D009223:Myotonic Dystrophy / Q000235:genetics* / Q000473:pathology*