Considerations for diverse RYR1 variants in malignant hyperthermia susceptible patients: a report of two cases

Malignant hyperthermia (MH) is an autosomal dominant pharmacogenetic disorder primarily triggered by halogenated volatile anesthetics, succinylcholine, or cisatracurium. This report describes two cases exhibiting typical MH symptoms, including hyperthermia, hypercarbia, tachycardia, and acidosis, but with notable differences in the time of onset and symptom severity. The variable expression of MH may be influenced by multiple factors, such as the potency of the triggering agent, its dosage, the duration of exposure, and the “incomplete penetrance” of genetic variants. The novel RYR1 gene variants reported in this study may contribute to the Genomic Variant Database for this condition.