Causes

Malignant hyperthermia susceptibility (MHS) is caused by a genetic defect (mutation). The abnormal gene increases your risk of malignant hyperthermia when you're exposed to certain anesthesia medications that trigger a reaction. The abnormal gene is most commonly inherited, usually from one parent who also has it. Less often, the abnormal gene is not inherited and is the result of a random gene mutation.

Different genes can cause the disorder. The most commonly affected gene is RYR1. More rarely affected genes include CACNA1S and STAC3.