CACNA1S and rhabdomyolysis: Current research indicates that mutations in the ryanodine receptor 1 (RYR1) and calcium channel, voltage-dependent, L type, alpha 1S subunit (CACNA1S) genes are closely associated with the pathogenesis of MH.[8] The symptoms of MH include elevated end-tidal carbon dioxide levels, rapid and severe hyperthermia, muscle rigidity, apnea, tachycardia, hyperkalemia, and rhabdomyolysis.