A myopathy that is characterized by distinctive facies, ptosis, downslanted palpebral fissures, widely spaced eyes, epicanthal folds, low-set ears, malar hypoplasia, micrognathia, high-arched palate, clinodactyly, single palmar crease, pectus excavatum, winging of the scapulae, lumbar lordosis, and mild thoracic scoliosis. Pathogenic variants in RYR1 have been found in some individuals with King-Denborough syndrome.