RYR1 and Malignant hyperthermia: Recent findings indicate that several amino acid substitutions in mammalian skeletal muscle RYR1 are associated with malignant hyperthermia, environmental heat stroke, and exercise-induced rhabdomyolysis (Wappler et al. 2001; Davis et al. 2002; Treves et al. 2005; Vladutiu et al. 2011).