Malignant Hyperthermia - 4
MH - Incidence/Inheritance

Fulminant syndrome: 1 in 200,000 anesthetics without succinylcholine vs 1 in 60,000 anesthetics that include succinylcholine. Note that the incidence of fulminant MH can be reduced 3 to 4 fold by avoiding the use of succinylcholine.
"Abortive," milder form: 1 in 5,000 anesthetics with succinylcholine. (More likely in children.)

Human malignant hyperthermia is inherited as an
autosomal dominant
trait with variable penetrance and expression. (In contrast, swine PSS inheritance is autosomal recessive!)
In MHS pigs and in some MHS humans, the disorder seems to be due to a specific mutation in the ryanodine receptor (RYR or RYR1) gene, mapped to region q 12-13 of chromosome 19. However, at least 29 other specific genetic defects in that gene and in other genes, (including one on 17q) cause MH in other human families. So, MH in humans is a heterogeneous genetic disorder.

Greg Gordon MD