Heart Disease in Cats: What a New Genetics Study Means for Your Cat
Hypertrophic cardiomyopathy, or HCM, is the most common inherited heart disease in cats. The heart muscle thickens, and over time this can lead to heart failure, blood clots or sudden death. Many cats look perfectly well until the disease is advanced.
A new genetics study set out to find the hidden genes behind it. The honest answer: it did not find a simple one. That is still useful for you to know.
What does the evidence say?
The study was published in 2025 in the journal G3: Genes | Genomes | Genetics by Joanna Kaplan, Joshua Stern, Katherine Meurs and colleagues, mostly from US veterinary schools (doi.org/10.1093/g3journal/jkaf153).
The team read the full DNA of 138 domestic cats, 109 with HCM and 29 healthy. They looked for variants that cause the disease or make it worse, and found no single variant or combination that did so. They did spot a few rare changes in genes already linked to human HCM in affected cats.
In a second group of 42 cats, they studied which genes were switched on or off in heart tissue. Sick hearts showed clear differences from healthy ones. That may eventually lead to new blood tests or treatments.
What the study did not show: a DNA test for the average cat. The authors note that, as in people, the cause stays unknown in many cases. Only two gene variants are firmly recognized as causes, one in Maine Coons and one in Ragdolls, and a Sphynx finding was not confirmed by other groups.
What this means for your cat
Most cats in Chile and Latin America are mixed-breed domestic cats, the very kind this study focused on. For them, no genetic test can promise a heart is healthy. A normal result would not rule out HCM, so the heart itself needs checking.
At home
- Count your cat's breathing while asleep and calm. Write the number down occasionally so you notice changes.
- Watch for tiring quickly, hiding, poor appetite or open-mouth breathing.
- Keep stress low during hot summer spells, as panting in a cat is never normal.
When to call the vet
- Fast or labored breathing: go the same day.
- Sudden weakness or dragging of the back legs, cold paws or crying out in pain: this can be a clot and is an emergency.
- A heart murmur heard at a checkup: ask about an echocardiogram, ideally with a veterinary cardiologist. These are available in Santiago and other large cities, though less so in smaller towns.
If you have a Maine Coon or Ragdoll, or plan to adopt one, ask the breeder about genetic testing of parents and heart screening. Those tests have helped lower HCM in these breeds.
Remember that other illnesses, like an overactive thyroid or high blood pressure, can also thicken the heart, so a vet needs to rule them out. Always consult your veterinarian before changing care for your cat.
Sources
Original source: ncbi.nlm.nih.gov