Detection of the T1640C RYR1 mutation indicating malignant hyperthermia in dogs

Malignant hyperthermia (MH) is a clinical syndrome exhibiting elevation of expired carbon dioxide, hyperthermia, muscle rigidity, rhabdomyolysis, acidosis and hyperkalaemia, as well as cardiac dysrhythmia and renal failure. The syndrome manifests itself as a response to anaesthetic agents, such as e.g., halothane, desflurane, and succinylcholine. Depending on the animal species, MH is characterised by autosomal dominant or recessive inheritance, and so far two genes have been identified whose mutations can be linked to MH: RYR1 and CACNA1S. In different species, various mutations of the RYR1 gene have been described which may underlie MH. One of these mutations in dogs is T1640C, which results in the substitution of alanine for valine of the amino acid 547 (V547A) in the RYR1 protein. In our work, we aimed to investigate MH at the DNA level by identifying the T1640C mutation in a group of 50 dogs. For this purpose we used the PCR-RFLP technique, and in six dogs also direct sequencing of PCR products and subsequent comparison of their sequences with the RYR1 gene sequence in an online database. The results of our study show that none of the dogs analysed had any mutant allele of the RYR1 gene, indicating that none should be affected by MH.