Part 6:
Devon Rex Health Concerns

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The Devon Rex is widely regarded as a unique, wonderful and highly sought after breed with an engaged and dedicated breeder community. That reputation did not happen by accident or overnight. And many steps towards health and progress have been made along the way. Like all pedigreed cats, Devons carry identifiable health risks, some inherited, some multifactorial. The long-term health of the breed depends on recognizing those risks honestly, screening appropriately, and avoiding poor solutions (like breeders who do no testing or DNA alone for instance).

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This article reviews the primary health concerns known in the Devon Rex, how they are monitored today, and what responsible breeders and veterinarians are doing to manage risk and improve outcomes over time.

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Hypertrophic Cardiomyopathy (HCM)
 

Hypertrophic cardiomyopathy is not a Devon Rex–specific problem. It is the most common heart disease in cats overall, seen in random-bred populations as well as pedigreed ones. What differs between breeds is incidence and risk (basically: how common it is), not exclusivity. Certain breeds, such as Maine Coons, Ragdolls, Sphynx, Devon Rex, British Shorthair and others are monitored more closely because population data and clinical experience suggest higher-than-average prevalence, not because the disease is unique to them.
 

The core challenge: late-onset disease
 

HCM presents a fundamental breeding problem because it can often be late-onset. Many cats:

• Have structurally normal hearts when young

• Develop measurable changes years later

• May not show symptoms until disease is advanced
   

This creates an unavoidable reality:
We cannot reliably breed “away” from late-onset HCM, because cats have already reached the age past which they should breed before disease is detectable. This is a limitation of biology.
 

What can be done: early detection and conservative selection

While HCM cannot be eliminated, early onset HCM and its impact can be reduced through systematic monitoring. This is why ethical Devon Rex breeders rely on serial echocardiography performed by veterinary cardiologists.

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Best practice includes:

• Baseline echocardiograms prior to breeding

• Annual echocardiograms through early adulthood, when early structural changes are most likely to appear

• Removal of cats from breeding at the first indication of concerning changes

• Longitudinal tracking of siblings, parents, and offspring
   

This approach does not “guarantee” a cat will never develop HCM, but it meaningfully reduces the likelihood of producing kittens from cats with early or familial disease expression.
 

Why extended HCM guarantees from breeders are rare

Given that we can only help predict early onset (1-6 years of age or so) HCM, most breeders limit health guarantees to one or two years. Short guarantees reflect that uncertainty.
 

At PureX Devon Rex, a six-year HCM guarantee is possible specifically because of:

• Consistent cardiologist-performed echocardiography across breeding cats

• Conservative breeding decisions that prioritize cardiac data

• Multi-generational health tracking within the cattery’s lines
   

A longer guarantee does not imply HCM risk is “solved.” It reflects confidence in monitoring, restraint, accountability and a willingness to stand behind breeding decisions during the window when early onset HCM is most likely to emerge.​

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Congenital Myasthenic Syndrome (CMS / “Spasticity”)

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Congenital Myasthenic Syndrome is a neuromuscular disorder affecting the communication between nerves and muscles. Historically referred to as “spasticity” in the Devon Rex, affected kittens may show muscle weakness, exercise intolerance, tremors, or collapse.

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A condition largely controlled.... but not gone

CMS is now rare in the Devon Rex, largely due to focused efforts by breeders in the late 1990s and early 2000s once the genetic cause was identified. This is a clear example of how coordinated health initiatives can successfully reduce disease prevalence in a breed.

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Despite its rarity, CMS remains relevant because:

• It is autosomal recessive

• Carriers are clinically normal

• Without testing, it can re-emerge silently
   

Responsible breeders continue to test for CMS.

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Polycystic Kidney Disease (PKD)

PKD causes progressive kidney cyst formation and eventual renal dysfunction. It is most commonly associated with Persian-derived lines but remains relevant in any breed with historical outcross influence.

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In the Devon Rex:

• PKD is not common, but not impossible

• Screening is straightforward and reliable

• Affected cats should not be bred

• DNA detectable versions are not the only type of PKD
   

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Dermatologic and immune-mediated conditions

Devon Rex cats can be predisposed to inflammatory or immune-mediated skin conditions, including recurrent dermatitis and conditions such as urticaria pigmentosa.

These conditions:

• Are typically multifactorial

• Do not have DNA tests

• Vary in severity and manageability
   

Breeders manage risk by tracking patterns within lines, avoiding repeat pairings that produce severe cases, and educating owners on long-term skin care.

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DNA Testing Is a Tool---Not a Substitute for Good Sense in Breeding

Modern genetic testing has transformed feline breeding, but it is often misunderstood by both breeders and buyers.

To put it in context:

• Cats have approximately 20,000 genes

• Only about 250 genes are currently associated with known diseases or conditions

• Roughly only 50 of those are commercially testable as of 2026
   

Most health conditions in cats, including HCM, skin disease, immune dysfunction, and many neuromuscular issues, are polygenic, influenced by multiple genes and environmental factors.
 

This is why:

• A normal DNA panel does not equal a healthy cat (remember, so many things cannot be tested!)

• A breeder who relies only on DNA testing is missing critical information

• Clinical screening, longitudinal lineage tracking, and restraint in breeding decisions remain essential
   

What Ethical Devon Rex Breeding (when it comes to health) Looks Like

Ethical Devon Rex breeders combine multiple approaches:

• Clinical screening (echocardiograms, veterinary oversight)

• Targeted DNA testing for known, relevant conditions

• Pedigree and family tracking

• Avoiding Genetic Bottlenecks

• Transparency with veterinarians and buyers about what is known AND what is not
   

The goal is not (and cannot be) to promise perfection, but rather to continuously reduce risk and improve predictability while preserving the long-term health and diversity of the breed.