Background: Malignant hyperthermia susceptibility is a pharmacogenetic disorder in which susceptible individuals may develop a potentially life-threatening hypermetabolism when exposed to certain anaesthetic agents. The most common diagnostic method is the in vitro contracture test (IVCT) of skeletal muscle biopsies. There is a wide variation in the size of contractures between susceptible individuals and the reproducibility of the test in humans has not been evaluated.
Methods: We have performed the IVCT in 4 monozygote pairs of twins, which gave us on opportunity to study the reproducibility.
Results: The clinical diagnoses were consistent in all twin pairs, although slight differences in contractures and thresholds were seen.
Conclusion: In this material the reproducibility of the IVCT was found to be satisfactory.