The genetic basis of malignant hyperthermia.

Malignant hyperthermia (MH) susceptibility remains the commonest cause of death owing to general anaesthesia. In humans, genetically predisposed to MH, anaesthesia can induce skeletal muscle rigidity, hypermetabolism and hyperthermia, which if not immediately reversed can lead to tissue injury and death. In swine, the corresponding condition leads to stress-induced deaths and devalued meat products. Aberrant behaviour in the calcium (Ca2+) release channel (the ryanodine receptor) of skeletal muscle sarcoplasmic reticulum has been implicated in the cause of both the porcine and human syndromes by biochemical, physiological and molecular genetic analysis. In swine, a single mutation in the ryanodine receptor gene (RYR1) can account for all cases of MH in all breeds, but a series of different RYR1 mutation are uncovered in human families with MH. In addition, the lack of linkage between MH and RYR1 in some families indicates a heterogeneous genetic basis for the human MH.