RYR1 and myositis disease: Accordingly, in a study on patients with statin-induced myositis, most (7 of 9) of the in vitro muscle tests showed halothane- and caffeine-induced contractures suggestive of impaired SR Ca2+ control and, in 1 patient, the abnormality was consistent with malignant hyperthermia, a disorder linked to variants in RYR1(80).