Pathogenesis: 1. Dysferlinopathy is an autosomal recessive skeletal muscle disease caused by a mutation in DYSF that results in abnormal dysferlin protein expression; the DYSF gene encodes the DYSFERLIN protein. 2. The role of DYSFERLIN protein is to repair damaged skeletal muscle cell membranes: under physiological conditions, myocyte membranes break under mechanical stress; if they are not repaired in time, myocytes will degenerate and become necrotic. 3, DYSFERLIN protein defects lead to difficulties in repairing cell membranes after they are physiologically disrupted; affecting membrane stability and membrane repair may also trigger inflammatory cascade reactions, and multiple factors cause irreversible damage to muscle fibers. Clinical features: adolescent onset; three types: classified according to the early involvement of muscle groups: 1. Miyoshi myopathy (Miyoshi myopathy MM) type: the posterior group of calf muscles are involved first; 2. limb-girdle muscular dystrophy 2B (LGMD 2B) type: proximal muscles are involved first, especially in the lower limbs; 3. distal anterior compartment myopathy (DACM) type: the anterior tibial muscles are involved first; muscle enzymes: blood Myoenzymes: significant elevation of CK in blood (35-200 fold); this is mainly due to the destruction of myocyte membrane; EMG: myogenic changes Pathology: typical myotonic dystrophy; active inflammatory response; immunohistochemical staining shows myocyte membrane dysferlin protein deficiency; Diagnosis: genetic testing is the gold standard, Western blot detects dysferlin deficiency in monocytes, combined with clinical manifestations can also diagnose dysferlinopathy dysferlinopathy can be diagnosed by Western blot.