Hypertrophic Cardiomyopathy (HCM) is the most common form of heart disease in cats. Onset of clinical symptoms usually occurs in middle age however, cats as young as one have been described. Cats with severe HCM and heart failure usually only live for a few months.

The inherited form of HCM is autosomal dominant, which means that carriers or heterozygotes (ie, those having one copy of the gene) will be affected. Although all cats with the mutation will be affected, the age of clinical onset and severity can vary considerably.

It is important to note that there are many forms and causes of HCM. HCM leads to a thickening of the heart wall, particularly on the left side. This in turn, can lead to heart failure, embolism and death.

Two specific mutations at different sites on the MYBPC3 gene have been found to be associated with HCM in Maine Coon and Ragdoll cats, respectively. The MYBPC3 gene is partly responsible for the heart’s ability to contract. These specific mutations result in the production of faulty proteins, which the heart tries to compensate by producing more. This overproduction can result in thickening or hypertrophy of the heart.

A Positive Result ?

A positive test result means that the cat will be effected in its lifetime.However the DNA test cannot predict the age at which clinical onset occurs nore the diseases severity. Some have found that males may get the disease at an earlier age and may have a more severe form.

A Negative (Clear) Result ?

A “clear” result means that the cat does not have the specific mutation that has been found to be associated with HCM in the breeds mentioned. As the test does not detect other causes of HCM, a “clear” result does not mean the cat will never develop HCM.

Breeding outcomes.

The table below summaries the probability of affected offspring by various matings.

Percentage of Offspring expected to be affected.

Two DNA tests are available that identify the specific mutations that have been associated with HCM in Maine Coon and Ragdoll cats. They identify mutations that were described by Drs Meurs and Kittleson and published in the scientific journals Genomics & Human Molecular Genetics1.

The tests are able to be performed on a simple cheek swab sample.

To get your cats tested, simply request a sample collection pack and submission form and mark either HCM-Maine Coon or HCM-Ragdoll.

1. Genomics, 2007, 90;261-264. Human Molecular Genetics,2005, 14;3587-3593.

• Request for free DNA collection sample kit
• View sample collection procedure