Calpainopathy is characterized by symmetric and progressive weakness of proximal limb-girdle muscles. Clinical findings of calpainopathy include the tendency to walk on tiptoe, difficulty in running, scapular winging, waddling gait, laxity of the abdominal muscles, Achilles tendon shortening, and scoliosis. Affected individuals typically do not have cardiac involvement or intellectual disability. Three autosomal recessive calpainopathy phenotypes have been identified based on the distribution of muscle weakness and age at onset: Pelvifemoral limb-girdle muscular dystrophy (LGMD) (Leyden-Möbius LGMD) phenotype, the most frequently observed calpainopathy phenotype, in which muscle weakness is first evident in the pelvic girdle and later in the shoulder girdle, with onset that may occur as early as before age 12 years or as late as after age 30 years. Scapulohumeral LGMD (Erb LGMD) phenotype, usually a milder phenotype with infrequent early onset, in which muscle weakness is first evident in the shoulder girdle and later in the pelvic girdle. HyperCKemia, usually observed in children or young individuals, in which individuals are asymptomatic and have high serum creatine kinase (CK) concentrations. The autosomal dominant form of calpainopathy is clinically variable, ranging from almost asymptomatic to wheelchair dependence after age 60 years in a few individuals; phenotype is generally milder than the recessive form.