often present with painful and marked weakness and/or loss of muscle mass in the proximal musculature, particularly in the shoulder and pelvic girdle (see weakness of the lower limb(s) / weak in the knees)
hip extensors are often severely affected, leading to particular difficulty in ascending stairs and rising from a seated position
weakness is generally progressive, accompanied by lymphocytic inflammation (mainly cytotoxic T lymphocytes)
sclerodactyly, dysphagia or interstitial lung disease may occur