Background: Calpainopathy is comprised of a group of myopathies caused by deficiency in calcium-activated, neutral protease (calpain-3). In this study we identify calpainopathy in a cohort of Chinese patients with unclassified myopathy and analyze its clinical and pathological features. Methods: Sixty-six muscle biopsies were selected for combined Western blotting of dysferlin and calpain-3 after immunohistochemical staining. Clinical and pathological parameters of 15 confirmed calpainopathy cases were determined. Results: The diagnosis of calpainopathy in 15 Chinese patients was confirmed by Western blot analysis. Fourteen subjects had progressive proximal muscle weakness; 1 presented with bilateral distal muscle atrophy of the lower extremities. Scapular winging was observed in 12 patients (80%), and joint contractures were found in 10 others (66.7%). Histopathological studies showed a high prevalence of lobulated fibers (66.7%). Conclusions: Chinese patients with calpainopathy share some common clinical and pathological features with the reported characteristics of non-Chinese patients. Muscle Nerve, 2011
