Malignant Hyperthermia (MH)
MH
Malignant Hyperthermia (MH) is a genetic muscle disorder that can cause a life-threatening condition in affected horses that is triggered by exposure to anesthetics, extreme exercise, or stress. The mutation causes a change in the release of calcium ions within skeletal muscles which can trigger a hyper-metabolic state that can be fatal. Common symptoms include high body temperature, increased heart rate and blood pressure, sweating, acidosis, and muscle rigidity. Symptoms can develop rapidly and require immediate treatment to prevent death. It is important to note that horses carrying the MH mutation in combination with the PSSM1 mutation can suffer more severe clinical symptoms than horses carrying the MH mutation alone.
Reading Your Results
A. (CLEAR/NORMAL):
These horses have two copies of the normal gene and will neither develop Malignant Hyperthermia nor pass this mutation to their offspring.
B. (CARRIER/NOT AFFECTED):
These horses have one copy of the normal gene and one copy of the mutation associated with this disease. They will develop Malignant Hyperthermia which typically results in a hyper-metabolic state that can be fatal and will, if bred, pass the mutation to 50% of its offspring, on average.
C. (AT RISK/AFFECTED):
These horses have two copies of the mutation associated with Malignant Hyperthermia which typically results in a hyper-metabolic state that can be fatal.
Additional Details
Inheritances
Autosomal Dominant
Affected gene
RYR1
Chromosome
Ch. 10
Mutation
c.7360C>G; p.R2454G
Publication:
Aleman M, Nieto JE, Magdesian KG. Malignant hyperthermia associated with ryanodine receptor 1 (C7360G) mutation in Quarter Horses. J Vet Intern Med. 2009;23(2):329-334. [PubMed: 19220734].
