Hypertrophic Cardiomyopathy (HCM) – Maine Coon

20 June 2022

Hypertrophic cardiomyopathy is a heart disease characterized by thickening of the heart muscle (myocardium) leading to the development of heart failure and death.

Cardiomyopathy is a breed specific condition that is common in breeds such as Maine Coon, Ragdoll, Ocicat, British, Scottish Fold, American Shorthair and Bengal Cat. DNA testing is currently available for Maine Coons and Ragdolls.

The relative risk of developing cardiomyopathy in cats carrying one copy of the A31P mutation is approximately 1.8 compared to cats that do not have the mutation. However, the relative risk of developing cardiomyopathy in cats with two copies of A31P is about 18. Therefore, cats with one copy of the mutant allele are 1.8 times more likely to develop cardiomyopathy than cats with the normal-type allele. And cats with two copies of the mutant allele – 18 times as cats in the normal type allele and 10 times as cats with one copy of the mutant allele.

The mechanism of the development of this pathology is that with the thickening of the heart muscle, the volume of the left ventricle decreases, as a result of which the volume of blood pumped through it decreases. Stagnation develops, which initially leads to an increase in the left atrium, pulmonary veins, and then in later stages to the development of pulmonary edema and / or hydrothorax (accumulation of fluid in the pleural cavity). In some cases, symptoms such as shortness of breath and poor exercise tolerance can occur in the early stages.

Genotype Options:

N/N – Homozygous for the normal-type allele (both copies of the MYBPC3 gene do not contain the A31P mutation).

N/HCMmc – Heterozygous for the mutant-type allele (one of the copies of the MYBPC3 gene contains the A31P mutation).

HCMmc/HCMmc – homozygous for the mutant-type allele (both copies of the MYBPC3 gene contain the A31P mutation).

This test only detects the HCM-associated A31P mutation in Maine Coons or their crossbreeds as described by Meurs et al., 2005.

The presence or absence of the A31P mutation does not indicate the presence or absence of the disease, but only characterizes the degree of risk of its development.

! Mutation A74T – The association of this mutation with the clinical manifestation of the disease in Maine Coons has not been proven.

Hypertrophe Kardiomyopathie (HCM) – Maine Coon

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