Inclusion body myositis

From Ganfyd

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^[1]. Other proteins found also in the inclusion bodies of some forms of the condition include presenilin 1 ,sequestosome1 (p62)^[2], TAR DNA binding protein-43 (TDP-43)^[3] 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^[3] and clusters ("tangles") of paired-helical filaments, containing phosphorylated tau^[4]

References

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