title: Idiopathic inflammatory myopathies: inclusion-body myositis, polymyositis, and dermatomyositis.
abstract: In this review, the main emphasis is on new advances concerning sporadic inclusion-body myositis and hereditary inclusion-body myopathy. Polymyositis and dermatomyositis are reviewed briefly. Hypotheses are presented regarding the possible cause and significance of abnormally accumulated beta-amyloid protein, two other epitopes of beta-amyloid precursor protein, hyperphosphorylated tau, alpha 1-antichymotrypsin, ubiquitin, and prion protein in sporadic inclusion-body myositis and hereditary inclusion-body myopathy. Because most of those proteins are also accumulated at the neuromuscular junction, "junctionalization" of other muscle fiber nuclei is a possibility. Attention is given to the fact that vacuolated muscle fibers in hereditary inclusion-body myopathy may represent early changes because they are virtually free of congophilic amyloid deposit but, like sporadic inclusion-body myositis, contain large accumulations of beta-amyloid protein and prion.
authors: University of Southern California School of Medicine, Department of Neurology, Los Angeles 90017-1912.
authors: V
authors: V
authors: Askanas
authors: W K
authors: WK
authors: Engel
authors: M
authors: M
authors: Mirabella
mesh_terms: D000368:Aged; D016229:Amyloid beta-Peptides / Q000235:genetics; D016564:Amyloid beta-Protein Precursor / Q000235:genetics; D046508:Culture Techniques; D003882:Dermatomyositis / Q000235:genetics* / Q000473:pathology; D003937:Diagnosis, Differential; D006801:Humans; D002479:Inclusion Bodies / Q000473:pathology*; D008875:Middle Aged; D009132:Muscles / Q000473:pathology; D009220:Myositis / Q000235:genetics* / Q000473:pathology; D017285:Polymyositis / Q000235:genetics* / Q000473:pathology; D011328:Prions / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics
chemical_list: D016229:Amyloid beta-Peptides; D016564:Amyloid beta-Protein Precursor; D011328:Prions; D012333:RNA, Messenger