Sporadic<unk>  (sIBM) is an inflammatory muscle disease, characterized by slowly progressive weakness and wasting of the distal and proximal muscles, most apparent in the muscles of the arms and legs. In sporadic<unk>  [MY-oh-sigh-tis] muscle, two processes, one autoimmune and the other degenerative, appear to occur in the muscle cells in parallel. The inflammation aspect is characterized by the cloning of T cells that appear to be driven by specific antigens to invade muscle fibers. The degeneration aspect is characterized by the appearance of holes in the muscle (vacuoles), deposits of amyloid-related proteins within the cells and filamentous<unk> s (hence the name<unk>  of abnormal proteins.
sIBM is a rare disease, diagnosed in only about 5 people per million, although not much research exists on the number of cases and some doctors feel the numbers are much higher. sIBM is an age-related disease - its incidence increases with age and symptoms usually begin after 50 years of age. Its prevalence rises to about 35 cases per million in people over 50 (Dalakas 2006).   It is the most common acquired muscle disorder seen in older people, although about 20% of cases display symptoms before the age of 50. Weakness comes on slowly (over months or years) and progresses steadily and may lead to severe weakness and wasting of arm and leg muscles. It is slightly more common in men than women. Patients may become unable to perform daily living activities and most require assistive devices within 5 to 10 years of symptom onset. sIBM is not considered a fatal disorder - all things being equal, sIBM will not kill you (but the risk of serious injury due to falls is increased). There is no effective treatment for the disease.
Inclusion body myositis
Nemaline myopathy
Centronuclear myopathy
Dermatomyositis
Inflammatory myopathy
Lambert-Eaton myasthenic syndrome
Salih myopathy
Muscular dystrophy