Hypertrophic Cardiomyopathy Maine Coon Type (HCM)
Acronym: | HCM, HCM1 |
Gene: | MYBPC3 |
Mutation: | c.91G>C |
Inheritance: | Autosomal dominant (with decreased penetrance) |
Sample type: | CHS (Cheek Swab), WBE (Whole Blood EDTA) |
Genetics and characteristics
Hypertrophic cardiomyopathy Maine Coon type is an inherited disease affecting the Maine Coon cat breed. Feline hypertrophic cardiomyopathy (HCM), the most common heart disease in cats, is a clinically heterogeneous disorder that is characterized by progressive enlargement of the heart and thickening of the heart muscle, particularly of the left ventricle. Affected cats may progress into congestive heart failure, thromboembolic events, or sudden cardiac death. Sudden death has been noted in cats only a few years old although affected cats may live for 10 years or more before developing symptoms including exercise intolerance, fatigue, fainting, fluid collection in the lungs, abdomen, and limbs, or blood clots that arise in the heart and travel to the kidney, brain, or legs. Ultrasound screening is a common tool utilized by veterinarians to see this disorder, though it can be difficult to diagnose this condition.
The Maine Coon (MC) cat is predisposed to HCM. The true prevalence within the breed is not known, however, its frequency varies by geographic area. The prevalence ranges from moderately high in Germany (22%), Asia (30.9%) and North America (22.5% – 31.7%), to high in Italy and France (38.2% – 41.5%), to even higher in Australia -New Zealand (46.3%). A dominant mode of inheritance has been established in some breeds and a causative mutation in the myosin binding protein C gene has been identified in the Maine Coon breed specifically.
The Maine Coon heterozygotes (carriers) usually lack evidence of Hypertrophic cardiomyopathy Maine Coon type during the years at which they would most commonly be bred. Even homozygotes for the mutation (affected) might not have evidence of HCM until they are closer to middle age. Consequently, echocardiographic screening, especially of young cats, should not be the sole diagnostic to identify HCM-potential cats since genetic screening is needed to identify cats with HCM-associated mutations. At the very least Maine Coon breeders should genotype their cats to make sure they are not breeding heterozygous to heterozygous cats and thereby producing cats homozygote for the mutation.
Results Reported As
Test Result |
Interpretation of test result |
CLEAR |
Tested mutation was not detected in animal with „clear“ result. Animal tested as clear has wild-type allele in homozygous state (i.e. two pairs of healthy alleles). It will not develop disease caused by tested mutation.* It will pass only wild-type allele to its offspring. |
AFFECTED HETEROZYGOTE |
Tested mutation was detected in animal with „affected heterozygote“ result. Animal tested as affected heterozygote has one wild-type and one mutation allele, it is in heterozygous state. It is likely to develop disease caused by tested mutation.* It can pass wild-type or mutation allele to its offspring. |
AFFECTED |
Tested mutation was detected in animal with „affected“ result. Animal tested as affected has two copies of mutation alleles affecting the gene. It is likely the animal will experience a genetic disorder due to this mutation.** It will pass only mutation allele to its offspring. |
*Test excludes only tested mutation but not possible unknown mutations or factors that can lead to similar condition/symptoms.
**Penetrance of tested mutation, and potential unknown mutations or multiple other factors can possibly affect the likelihood of experiencing a genetic disorder.
References:
Godiksen, M.T., Granstrøm, S., Koch, J., and Christiansen, M. (2011). Hypertrophic cardiomyopathy in young Maine Coon cats caused by the p.A31P cMyBP-C mutation – the clinical significance of having the mutation. Acta Vet Scand 53, 7.
Longeri, M., Ferrari, P., Knafelz, P., Mezzelani, A., Marabotti, A., Milanesi, L., Pertica, G., Polli, M., Brambilla, P.G., Kittleson, M., et al. (2013). Myosin-binding protein C DNA variants in domestic cats (A31P, A74T, R820W) and their association with hypertrophic cardiomyopathy. J. Vet. Intern. Med. 27, 275–285.
Shelton, L. and Helmrich, H.G. (2006). Heritable diseases and abnormalities in cats.