Identification of a novel de novo RYR1 variant associated with malignant hyperthermia

Malignant hyperthermia (MH) is a severe reaction occurring upon the use of certain pharmacological agents during anaesthesia. The reaction typically includes an uncontrolled increase of body temperature, muscle spasms, tachycardia and hypercapnia. Identifying a genetic aetiology in MH patient allows diagnostic confirmation and genetic screening of relatives at risk. MH susceptibility (MHS) has extensively been associated with heterozygous missense variants in the RYR1 gene of dominant inheritance, but new variants are still to be discovered. We report here a novel de novo RYR1 variant c.487C>G p.(Arg163Gly) identified in a young boy who experienced a peroperative MH crisis. To the best of our knowledge, this is the first case reporting this new RYR1 variant, paving the way for future diagnosis, but genetic counselling and presymptomatic screening may vary depending on the classification that is used.