RYR1 and myopathy: We have shown that a mutation in Ryr1 that leads to the replacement of tyrosine with a serine at amino acid 524 in RyR1 (Y522S in humans, Y524S in mice), which cause both malignant hyperthermia and myopathy with cores, increases heat sensitivity, temperature-dependent SR Ca2+ leak, mitochondrial damage and oxidative/nitrosative stress5.