The Rycal S107, a 1,4–benzothiazepine derivative, inhibits calstabin1 depletion from RYR1 channels and improves muscle strength in mdx mice and also in 24-month-old mice with age-related muscle weakness and in ß-sarcoglycan-deficient (Sgcb−/−) mice, a model of limb-girdle muscular dystrophy [38,39,40]. Here, RYR1 is linked to limb-girdle muscular dystrophy.