Understanding Those Curly Devon Rex Genetics: What Every Buyer Should Know

Curious about the ever so curly Devon Rex? When considering a Devon Rex kitten, understanding the breed's genetics is crucial for making an informed decision. The Devon Rex is a breed known for its soft, curly coat, large ears, and affectionate nature. However, its unique genetic makeup also influences its coat type, health risks, and breeding considerations. This article will provide a comprehensive overview of Devon Rex genetics, supported by scientific insights and expert sources.

The Genetics Behind the Curly Devon Rex Coat

The defining feature of the Devon Rex is its soft, curly coat, which is caused by a mutation in the KRT71 gene (keratin 71). This recessive gene is responsible for hair structure, and in the Devon Rex, it leads to a reduction in guard hairs, giving the breed its distinctively short and wavy fur (Gandolfi et al., 2010).

A brown tabby Devon Rex kitten in the process of kitten molt.

Key Characteristics of the Devon Rex Coat:

The lack of guard hairs makes their fur exceptionally soft, but also sometimes more fragile.
Coat thickness and curliness vary from cat to cat, even within the same litter, as many genes have an influence on the thickness and degree of curl. However, an experienced breeder, familiar with their lines should be able to give you a reasonable indication of whether a kitten will have a full coat as an adult (as they should), or whether they are likely to always be sparse in the hair department. When breeding to the CFA, TICA, ACFA or CCA standard, a cat should be fully coated, but occasionally kittens are born to well coated parents that simply didn't wind up with as much coat as aimed for.
Some Devon Rex cats may experience seasonal or age-related bald patches (like kitten molt!) (Housley & Venta, 2006). Furthermore, the natural hair growth pattern on a Devon tends to leave some patches much thinner even on well coated (breed standard) individuals.
The Devon Rex mutation is distinct from the Cornish Rex mutation, which affects a different region of the KRT71 gene.

Genetic Health Concerns in the Devon Rex

All descendants of a single cat, the Devon Rex started with a limited gene pool, which increased the likelihood of inherited conditions. Over time and with research advancements, responsible breeders are now able to perform genetic testing to identify and reduce the risk of -some- of these diseases.

Common Genetic Health Issues:

Hypertrophic Cardiomyopathy (HCM): A heart condition that can have a genetic aspect( **but can also occur without a genetic component) affecting many cat breeds. HCM is one of the leading causes of death among all cats. Even domestic cats of no known breed origin. HCM causes thickening of the heart muscle, which can lead to heart failure. A 2021 study found a higher prevalence of HCM in Devon Rex cats and some other breeds compared to some others (Longeri et al., 2021). Presently there is no genetic test with proven results in the Devon Rex. Routine echocardiograms of breeding adults are the necessary requirement to screen for this in cats. Routine meaning on a regular basis, because an echo, is only a snapshot in time and does not mean an animal will remain clear as they age.
Hereditary Myopathy (Spasticity Syndrome): A rare neuromuscular disorder affecting muscle function. This condition, linked to a recessive genetic mutation, can cause generalized muscle weakness (Fyfe et al., 2008). Fortunately, due to the aggressive testing by many Devon breeders in the early 2000's, it's now very rare to find.
Patellar Luxation: A condition where the kneecap dislocates, affecting mobility. This is believed to have a genetic component, though environmental factors may contribute (O'Neill et al., 2018). Please keep in mind that cats have naturally more laxity in their joints than dogs..... but true luxation is still to be avoided in a breeders program at all costs.
Polycystic Kidney Disease (PKD): A hereditary condition characterized by the development of fluid-filled cysts in the kidneys. PKD can lead to kidney dysfunction and eventual failure. While more common in Persian and related breeds, testing is recommended for Devon Rex cats to ensure they are not carriers (Lyons et al., 2004).

Importance of Genetic and Physical Health Testing

Amongst other things, reputable breeders should conduct full DNA testing for hereditary diseases. HCM screenings, in particular, should be performed regularly via echocardiograms by a certified veterinary cardiologist. Truly, there is no excuse for the lack of these tests being performed.

Coat Color and Pattern Genetics

Devon Rex cats are accepted in all colours and patterns and so come in as wide variety of coat colors and patterns as is possible, governed by multiple genetic factors.

Solid Colors: Black, white, blue, red, cream, chocolate, and lilac.
Pointed Patterns: many Devon Rex cats carry the "point" gene (cs/cs), most recognizable in the Siamese breed, leading to blue eyes and color contrast at the extremities (Lyons, 2005).
Tabby Patterns: Governed by the Taqpep gene, which influences whether a cat has stripes, spots, or a classic swirl pattern.
Dilution: A recessive gene (d/d) that affects color intensity, creating softer shades like blue (diluted black), lilac (diluted chocolate) and fawn (diluted cinnamon) (Kaelin & Barsh, 2013).

Four curly Devon Rex Kittens, two of whom are a less common Fawn variant which is Dilute Cinnamon.

Ethical Breeding Practices and Genetic Diversity

Since the Devon Rex originated from a single cat discovered in Devon, England in 1960, the breed has a relatively narrow genetic base. Ethical breeders prioritize genetic diversity to prevent inbreeding-related health problems. To maintain or improve on that diversity, some breeders introduce outcross programs using carefully selected (and association approved) breeds such as the American Shorthair or British Shorthair. These breeds help broaden the Devon Rex gene pool while maintaining essential breed characteristics. However, genetic and physical health testing remains crucial for outcross individuals to ensure they do not introduce undesirable health conditions, such as PKD, or HCM which is prevalent in these breeds as well (Lyons et al., 2004).

Questions to Ask a Breeder:

Do you conduct genetic/physical testing or screening for HCM, myopathy, patellar luxation, and PKD?
How do you ensure genetic diversity in your breeding program?
Can you provide health screening certificates for the parents?

If someone cannot or is not willing to talk about these things with you, please re-consider if a kitten from that person is a wise choice or not. Breeders have an ethical obligation to have basic understandings of these concepts in order to make sound decisions about their programs.

Conclusion

Understanding the genetics of the Devon Rex helps potential owners make informed choices about their future pet. Selecting a breeder who prioritizes genetic health and ethical breeding ensures that you bring home a healthy, well-adjusted kitten.

At PureX Devon Rex, we are committed to responsible breeding, breed education, genetic and physical health, and transparency.

References

Fyfe, J. C., et al. (2008). "Hereditary myopathy in Devon Rex cats: A neuromuscular disorder."
Gandolfi, B., et al. (2010). "The KRT71 gene and its role in feline coat variation." Animal Genetics, 41(5), 493-496.
Housley, D. J., & Venta, P. J. (2006). "Hair coat genetics in domestic cats." Mammalian Genome, 17(1), 79-88.
Kaelin, C. B., & Barsh, G. S. (2013). "Coat color genetics in felines." Cell, 155(5), 1049-1054.
Longeri, M., et al. (2021). "Prevalence of HCM in Devon Rex cats." Journal of Comparative Pathology, 185, 54-61.
Lyons, L. A. (2005). "Genetic determinants of coat colors in cats." Genetics, 170(1), 437-448.
Lyons, L. A., et al. (2004). "Polycystic Kidney Disease in cats: Genetic basis and testing." Journal of Heredity, 95(5), 393-399.
O'Neill, D. G., et al. (2018). "Patellar luxation in cats: Prevalence and risk factors." BMC Veterinary Research, 14(1), 234.