Malignant hyperthermia / MHS (RYR1-related) - Dog

What does this test analyse?

This genetic test analyses the RYR1 c.1640T>C-variant in dogs. The condition is known as malignant hyperthermia, MH or malignant hyperthermia susceptibility / MHS.

What does this condition mean?

Malignant hyperthermia is a pharmacogenetic muscle reaction that usually remains invisible until a dog is exposed to triggering anaesthetic agents or certain muscle relaxants. Once triggered, body temperature can rise rapidly and muscle rigidity, fast breathing, cardiac rhythm problems and collapse may occur. The reaction can become life-threatening.

Inheritance and result

The trait is inherited as autosomal dominant. One copy of the variant is enough to cause susceptibility to the tested form. A dog with two copies carries an even stronger variant load; in both situations the result matters for anaesthesia planning, breeding selection and risk management.

Practical value of this test

This test has practical value because a carrier or positive dog can appear completely healthy. The result makes the genetic risk visible before anaesthesia, procedures or breeding decisions.

• Supports veterinarians and owners in safer anaesthesia and emergency planning.
• Helps breeders and breed clubs manage dominant risk variants in mating choices.
• Makes family-line investigation and selection more concrete.
• Provides clear information for dogs from breeds in which this RYR1 variant has been described.

Result in brief

• Clear (T/T): the tested variant was not detected.
• Carrier / positive (T/C): one copy was detected; this causes susceptibility to the tested form of MH.
• Positive with two copies (C/C): two copies were detected; this result should be treated as a highly relevant anaesthesia risk.