Inclusion body myositis
Inclusion body myositis (IBM) is a muscle disorder, in its sporatic-IBM (s-IBM) form in elderly adults, which is characterised by the presence of protein inclusion bodies and inflammatory muscle degeneration. It is the commonest intrinsic muscle disorder in those over 55 years of age. There are several other inclusion body myopathies (hereditary inclusion-body myopathies (h-IBM) with genetic transmission and no inflammation. Its cause is unknown and in particular a past claim that it was specifically associated with amyloid precursor protein has been noted to be inconsistent with the present primary evidence base. Other proteins found also in the inclusion bodies of some forms of the condition include presenilin 1 ,sequestosome1 (p62), TAR DNA binding protein-43 (TDP-43) ubiquitinated-proteins, apolipoprotein E, alpha-synuclein and phosphorylated tau. Findings include:
- Muscle weakness
- Abnormal EMG with myopathic motor units and spontaneous activity
- Muscle biopsy with rimmed vacuoles within muscle fibers and endomysial inflammation with focal invasion of muscle fibers and clusters ("tangles") of paired-helical filaments, containing phosphorylated tau
- ↑ Greenberg SA. How citation distortions create unfounded authority: analysis of a citation network. BMJ (Clinical research ed.). 2009; 339:b2680.(Epub)
- ↑ Nogalska A, Terracciano C, D'Agostino C, King Engel W, Askanas V. p62/SQSTM1 is overexpressed and prominently accumulated in inclusions of sporadic inclusion-body myositis muscle fibers, and can help differentiating it from polymyositis and dermatomyositis. Acta neuropathologica. 2009 Jun 26.(Epub ahead of print) (Link to article – subscription may be required.)
- ↑ a b Weihl CC, Temiz P, Miller SE, Watts G, Smith C, Forman M, Hanson PI, Kimonis V, Pestronk A. TDP-43 accumulation in inclusion body myopathy muscle suggests a common pathogenic mechanism with frontotemporal dementia. Journal of neurology, neurosurgery, and psychiatry. 2008 Oct; 79(10):1186-9.(Link to article – subscription may be required.)
- ↑ Askanas V, Engel WK, Yang CC, Alvarez RB, Lee VM, Wisniewski T. Light and electron microscopic immunolocalization of presenilin 1 in abnormal muscle fibers of patients with sporadic inclusion-body myositis and autosomal-recessive inclusion-body myopathy. The American journal of pathology. 1998 Apr; 152(4):889-95.
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