Hypertrophic Cardiomyopathy: Genetic Test for HCM!

Huge news for owners/breeders of Ragdolls, Maine Coons, and Sphynxes!

Opal, my beloved Sphynx girl.

In case you missed it last year, NC State came out with a genetic test for hypertrophic cardiomyopathy.

HCM is a deadly form of heart disease that certain breeds are genetically prone to.

NC State now offers genetic tests for Ragdolls, Maine Coons, and Sphynxes โ€” all it takes is a cheek swab, and each kit is only $40! Not only is this a massive help for owners and breeders of these cats to screen them, but it furthers the studies that NC State is doing on HCM.

Please click HERE for the link to the DNA test cheek swab request form if you have the eligible breeds and are interested in having them tested!

They are also offering discounts on litters of kittens whose swabs are submitted together.

๐™’๐™๐™–๐™ฉ ๐™ž๐™จ ๐™ƒ๐™ฎ๐™ฅ๐™š๐™ง๐™ฉ๐™ง๐™ค๐™ฅ๐™๐™ž๐™˜ ๐˜พ๐™–๐™ง๐™™๐™ž๐™ค๐™ข๐™ฎ๐™ค๐™ฅ๐™–๐™ฉ๐™๐™ฎ?

In summary, hypertrophic cardiomyopathy (HCM) causes the heartโ€™s ventricular walls to thicken, decreasing the efficiency of heart function and predisposing the patient to congestive heart failure and blood clot formation.

Cornell University has an AMAZING article that discusses HCM in depth.

Please click HERE to check out the Cornell article and learn more about HCM.

Here is the information posted by NC State last year regarding the DNA test and the identified HCM gene:


This does NOT mean if your Sphynx comes back negative ( -/-) that they will never get HCM or are โ€œfreeโ€ of HCM.

We here at NC State have very recently identified a DNA mutation in about 60% of affected Sphynx Cats. This mutation is also found occasionally in healthy adult Sphynx cats who do not have the disease. This referred to as โ€œincomplete penetranceโ€.

This means that even if a cat has the genetic mutation, the mutation may not actually penetrate or lead to the development in full disease in that cat. This is also a common finding in Maine Coons, Ragdolls and human beings with genetic mutations associated with Hypertrophic cardiomyopathy.

Importantly since this mutation only appears to have identified about 60% of affected cats, it appears likely that there is at least one other Sphynx cat HCM Mutation

DNA test results will indicate if the cat has the mutation on 1 copy of its 2 gene copies (called heterozygous) or both gene copies (homozygous). At this time, we do not know if the risk of developing disease is higher in cats that are homozygous for the mutation than heterozygous.

Our current interpretations of the possible test results are:

Negative ( -/- )

Negative cats have two copies of the normal, unmutated gene. Very importantly, the absence of the mutation in this cat does not mean that it will never develop the disease. It means that it does not have the only known mutation that can cause the disease in the cat at this time. In the future, additional mutations may be identified that may be tested for as well.

Positive Heterozygous: (+/-)

Cats who are Positive Heterozygous for the HCM mutation have 1 copy of the mutated gene and 1 copy of a normal gene. Cats that are positive for the test will not necessarily develop significant heart disease and die from the disease. Some cats will develop a very mild form of the disease and will live quite comfortably. We recommend annual evaluation by an echocardiogram and discussion with a veterinarian for treatment options if hypertrophy develops.

Positive Homozygous: (+/+)

Cats who are Positive Homozygous for the HCM mutation have 2 copies of the mutated gene and may have a greater likelihood of showing severe signs of hypertrophic cardiomyopathy. Importantly, breeding decisions should be made carefully.

At this time, we do not know what percent of the overall Sphynx cat population carry at least one copy of the gene.

Removal of a large number of cats from the breeding population could have a negative impact on the breed. Remember that HCM affected cats also carry other important good genes that we do not want to lose from the breed.

In general, we recommend not breeding homozygous cats and, if needed, breeding heterozygotes to unaffected cats to decrease the risk of producing affected cats. As we move forward, we should try to select more and more negative kittens from these lines to use for breeding. Keep in mind that we are continually learning about this disease and recommendations will be altered as we obtain more information.


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