Inclusion-body myositis: a myodegenerative conformational disorder associated with Abeta, protein misfolding, and proteasome inhibition

Neurology. 2006 Jan 24;66(2 Suppl 1):S39-48. doi: 10.1212/01.wnl.0000192128.13875.1e.


Sporadic inclusion-body myositis (s-IBM), the most common muscle disease of older persons, is of unknown cause and there is no successful treatment. We summarize our most recent findings, which provide a better understanding of the steps in the pathogenetic cascade. We suggest that s-IBM is primarily a myodegenerative disease. Intriguing are the phenotypic similarities between s-IBM muscle fibers and the brains of Alzheimer disease, the most common neurodegenerative disease of older persons. In s-IBM, abnormal accumulation of the amyloid-beta (Abeta) precursor protein and its proteolytic fragment, Abeta, associated with the aging intracellular milieu of the muscle fiber, appear to be key upstream pathogenic events. We propose that the identified abnormal accumulation, misfolding, and aggregation of proteins, perhaps provoked by the aging milieu and aggravated by the oxidative stress, lead to the s-IBM-specific vacuolar degeneration and atrophy of muscle fibers.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Aged
  • Aging / pathology
  • Alzheimer Disease / metabolism
  • Alzheimer Disease / pathology
  • Amyloid beta-Peptides / metabolism
  • Humans
  • Middle Aged
  • Mitochondria, Muscle / pathology
  • Muscle Proteins / metabolism
  • Muscular Atrophy / pathology
  • Myositis, Inclusion Body / metabolism*
  • Myositis, Inclusion Body / pathology
  • Oxidative Stress
  • Phenotype
  • Proteasome Endopeptidase Complex / physiology
  • Protein Conformation
  • Protein Folding
  • Vacuoles / ultrastructure


  • Amyloid beta-Peptides
  • Muscle Proteins
  • Proteasome Endopeptidase Complex
  • ATP dependent 26S protease