Collaborative study of the frequency of the fluoride-resistant cholinesterase variant in patients with malignant hyperpyrexia.

Cholinesterase phenotyping studies have been carried out in two laboratories on blood specimens from 28 patients shown to be susceptible to malignant hyperpyrexia. In contrast to previously published reports, no evidence could be found for an increase in the frequency of the E1u E1f genotype above that known to occur in the general population.