title: Autosomal dominant late-onset quadriceps myopathy: three patients of a Taiwanese kindred.
abstract: OBJECTIVE
  Primary quadriceps weakness/atrophy is a rare disorder with variable etiologies; therefore, this disorder has been regarded as a clinical syndrome rather than a distinct entity. However, three affected patients of a Taiwanese family demonstrate a uniform pattern of quadriceps weakness and atrophy, their clinical manifestations and pattern of inheritance may suggest a new disease entity.
  
  
  METHODS
  Three patients in a Taiwanese kindred with selective quadriceps weakness and atrophy, which began after age 40 years, were examined. To disclose the confines of this disorder, muscle CT scans, electromyography, nerve conduction studies and muscle biopsies were performed; and to unravel and better understand the nature of this disorder, histopathological, ultrastructural, immunocytochemical and genetic studies were carried out.
  
  
  RESULTS
  In two patients with long-standing disease, muscle imaging showed marked atrophy and fat replacement of the anterior thigh muscles and electromyography showed a mixture of myopathic and neuropathic changes. Muscle histopathology on the mildly affected tibialis anterior showed myopathic changes with myofibrillar degeneration and secondary neurogenic alterations. Immunocytochemical staining was not diagnostic but excluded the dystrophinopathies and other well-known muscular dystrophies.
  
  
  CONCLUSIONS
  All previously identified diseases resulting in quadriceps weakness and atrophy have been ruled out and the present disorder appears to be a new disease entity of autosomal dominant late onset quadriceps myopathy.
authors.affiliation: Department of Neurology, Keelung Chang Gung Memorial Hospital, Taiwan. yyccsubo@adm.cgmh.org.tw
authors.forename: Yu-Yi
authors.initials: YY
authors.lastname: Chien
authors.forename: Ikuya
authors.initials: I
authors.lastname: Nonaka
authors.forename: Daryi
authors.initials: D
authors.lastname: Wang
mesh_terms: D000367:Age Factors; D000368:Aged; D001706:Biopsy; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018908:Muscle Weakness / Q000175:diagnosis / Q000208:ethnology / Q000235:genetics; D009133:Muscular Atrophy / Q000175:diagnosis / Q000208:ethnology / Q000235:genetics; D009135:Muscular Diseases / Q000175:diagnosis / Q000208:ethnology* / Q000235:genetics*; D010375:Pedigree; D052097:Quadriceps Muscle / Q000473:pathology* / Q000503:physiopathology*; D013624:Taiwan; D014057:Tomography, X-Ray Computed