BareDezyne Cattery · Health Education
HCM Testing in Sphynx Cats
What Hypertrophic Cardiomyopathy is, why it matters in the Sphynx breed, how testing works, and what to look for in a breeder who takes cardiac health seriously.
If you're researching Sphynx cats — whether you're considering adoption or simply want to understand the breed better — you'll encounter the term "HCM testing" frequently. It comes up in breeder listings, in Sphynx cat communities, and in any honest conversation about what distinguishes a responsible breeder from one who isn't.
HCM testing is not a formality or a marketing claim. It's a meaningful, substantive medical practice that has real consequences for the health and longevity of the cats produced by any breeding program. Understanding what it is, what it does, and what its limitations are will help you ask better questions and make more informed decisions — and that's exactly what this guide is for.
What Is HCM?
HCM stands for Hypertrophic Cardiomyopathy. It is a condition in which the walls of the heart's left ventricle thicken abnormally — a process called hypertrophy. As the walls thicken, the chamber of the heart becomes smaller, reducing its capacity to fill and pump blood efficiently. The heart muscle becomes stiffer, and over time, this can lead to impaired cardiac function, congestive heart failure, dangerous arrhythmias, or sudden cardiac death.
HCM is the most common form of heart disease in domestic cats overall. In the general cat population, it's estimated to affect 10–15% of all cats. In certain breeds — including the Sphynx, the Maine Coon, and the Ragdoll — the prevalence is significantly higher and has a known hereditary component. In Sphynx cats specifically, studies have found HCM rates that make the breed among the most at-risk in the feline world, which is why the Sphynx cat community has put such strong emphasis on systematic cardiac testing.
HCM in the Sphynx Breed Specifically
The Sphynx breed has been studied extensively for HCM, and a specific genetic mutation (MYBPC3 A31P) has been identified as a contributing factor in some Sphynx cats. However, and this is important: HCM in Sphynx cats is not solely explained by this one mutation. Cats who test DNA-negative for the known mutation can still develop HCM through other mechanisms, which means echocardiographic screening remains essential even in DNA-negative cats.
This genetic complexity is part of why responsible breeders use both forms of testing — not one or the other, but both together — because each provides a different and complementary form of information about a cat's cardiac health and genetic risk profile.
Echocardiographic (Echo) Screening
An ultrasound of the heart performed by a board-certified veterinary cardiologist. It assesses the heart's structure in real time — wall thickness, chamber dimensions, and functional characteristics. A negative echo means the heart appears structurally normal at the time of examination. Because HCM can develop or progress over time, echo screening should be repeated regularly — annually for active breeding cats is the standard of care.
HCM DNA Testing
A genetic test (typically a cheek swab) that detects the presence of the known MYBPC3 A31P mutation associated with HCM in Sphynx cats. It's a one-time test. A DNA-negative result means the cat does not carry the known mutation — but does not guarantee they won't develop HCM through other pathways. DNA testing is an important piece of the picture, not the whole picture.
What "HCM Negative" Means and What It Doesn't
When a breeder says their cats are "HCM Negative," they typically mean those cats received a clear result on their most recent echocardiogram — the heart appeared structurally normal at the time of examination. This is a meaningful, positive result. It means the cat is not currently showing signs of the condition that the echocardiogram can detect.
What it doesn't mean: a permanent guarantee that HCM will never develop. HCM can appear or progress at any age, which is why annual retesting of breeding cats is so important. A test result from three or four years ago provides much less assurance than one from six months ago.
When evaluating a breeder's HCM testing claims, always ask:
When was the most recent echo performed? By whom — a general vet or a board-certified veterinary cardiologist? Has DNA testing also been performed? Can you see the actual documentation? A responsible breeder will have clear, dated reports they'll share without hesitation.
How BareDezyne Approaches HCM Testing
At BareDezyne, cardiac health is not optional or aspirational — it is a foundational requirement of our breeding program. Every breeding cat in our active program carries current HCM Negative echocardiographic results, tested by a board-certified veterinary cardiologist. Every breeding cat has also been DNA tested for the MYBPC3 A31P mutation.
Our HCM testing commitment reflects what we believe is the minimum responsible standard for any ethical Sphynx breeding program. We don't use general veterinarians for cardiac screenings — cardiologist-level expertise is necessary for meaningful results. We don't test once and consider it done — we maintain current testing status for every active breeding cat on a regular schedule. And we make the documentation available to every family who adopts from us, because we believe transparency is as important as the testing itself.
The kittens we produce are not guaranteed to never develop HCM — no kitten from any program can be given that guarantee, given the complexity of the condition. But kittens from two HCM-tested, HCM-negative parents have a meaningfully better statistical starting point than those from untested parents, and we believe every family deserves that advantage.
What Should You Ask a Sphynx Breeder About HCM Testing?
If you're in the process of evaluating Sphynx breeders, cardiac health should be a primary topic of conversation. Here are the specific questions worth asking — and what strong answers look like:
"Are both breeding parents HCM tested?"
Strong answer: Yes, both parents — and the documentation is available to share with you. Weak answer: One parent is tested. Concerning answer: Our cats come from healthy lines / we've never had a cat with heart problems.
"Who performed the echocardiogram?"
Strong answer: A board-certified veterinary cardiologist (look for DACVIM-Cardiology credential). Weak answer: Our regular vet checked their hearts. A general veterinarian using a stethoscope is not a substitute for an echocardiogram by a cardiologist.
"When was the most recent test performed?"
Strong answer: Within the past twelve months for active breeding cats. Concerning answer: The cat was tested as a kitten or two or three years ago without follow-up.
"Has DNA testing been performed?"
Strong answer: Yes, both DNA testing and echocardiographic screening are performed. Helpful note: DNA testing alone is not sufficient — it needs to be combined with regular echo screening.
⚠ Red flag to watch for:
Breeders who describe their cats as "heart healthy" or "from healthy lines" without providing actual echocardiographic documentation are not the same as breeders with documented HCM Negative test results. The distinction is significant. Always request actual documentation — dated cardiologist reports — rather than accepting verbal assurances.
HCM Monitoring for Sphynx Cat Owners
As a Sphynx cat owner, understanding HCM also means knowing how to monitor your cat's cardiac health throughout their life — even if they came from a well-tested breeding program.
We recommend that all Sphynx cats receive a baseline echocardiogram in young adulthood (around two to three years of age), with follow-up screening every two to three years thereafter, or more frequently if any concern arises. Annual wellness exams with cardiac auscultation by your veterinarian are also important — a murmur or abnormal rhythm detected by your vet is a prompt to schedule a cardiology consultation.
Pet insurance with cardiac coverage is strongly recommended for Sphynx cats. The cost of echocardiograms and any cardiac treatment can be significant, and having coverage in place from a young age — before any condition develops — ensures that you can make the best medical decisions for your cat without financial constraints limiting your options.
HCM Testing FAQ
If a Sphynx cat's parents are both HCM negative, can the kitten still develop HCM?
Yes — HCM can still develop in a kitten from tested, negative parents. Testing the parents significantly reduces the statistical risk, but it does not eliminate it entirely. HCM is a complex condition influenced by multiple genetic and potentially environmental factors, and not all contributing factors are captured by current testing. This is why we also recommend that all Sphynx cats receive periodic echocardiographic monitoring as adults, regardless of their parents' test results.
What parent testing does is meaningfully improve the odds — and that improvement is real, significant, and worth choosing for.
What is the MYBPC3 mutation and why does it matter in Sphynx cats?
MYBPC3 is the gene that encodes myosin-binding protein C, a structural component of the heart muscle. The A31P mutation in this gene has been identified as a genetic risk factor for HCM in Sphynx cats. Cats who are DNA-positive for this mutation have a meaningfully elevated risk of developing HCM compared to those who are negative.
However, it's important to understand that not all Sphynx cats with HCM carry this mutation — meaning the mutation is a risk factor, not the only cause. DNA testing for this mutation is a valuable tool but must be used alongside regular echocardiographic screening, not instead of it.
How much does an HCM echocardiogram cost for a cat?
The cost varies by region and facility, but echocardiograms by board-certified veterinary cardiologists typically range from approximately $350 to $600 per exam in the United States. This is one reason why some breeders choose not to do them — the cost per cat per year adds up significantly across an entire breeding program. But for a responsible breeder, this is a non-negotiable investment, not an optional expense.
For owners monitoring their own Sphynx cat's health, pet insurance that covers cardiac conditions can help offset this cost significantly. It's worth obtaining a policy before any condition develops, as pre-existing conditions are typically excluded.
Are there symptoms of HCM I should watch for in my Sphynx cat?
This is one of the most challenging aspects of HCM: in many cats, it causes no obvious symptoms in its early stages. By the time clinical signs appear — labored breathing, open-mouth breathing, lethargy, pale gums, sudden weakness in the hindquarters — the condition may already be quite advanced.
This is exactly why periodic echocardiographic monitoring matters. It can detect structural changes in the heart before symptoms develop, allowing for earlier intervention and management. If you ever notice any of the symptoms above in your Sphynx cat, please seek veterinary attention immediately — these can indicate cardiac decompensation and should be treated as urgent.
Can HCM in cats be treated?
HCM cannot be cured, but it can often be managed. Medications — including atenolol, diltiazem, and furosemide, among others depending on the stage and presentation — can help control symptoms, reduce fluid accumulation, and improve quality of life. Some cats with HCM live for years with good quality of life on appropriate medication and monitoring.
Early detection through regular echocardiographic monitoring provides the best opportunity for effective management. This is why we recommend regular cardiac screening for all Sphynx cats throughout their lives, not just as kittens, and why we encourage our families to establish care with a veterinarian who is willing to refer to a cardiologist when appropriate.
Adopt from a program that takes cardiac health seriously
At BareDezyne, HCM testing is not a claim — it's a documented, ongoing commitment built into every breeding decision we make.
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