There has been growing discussion among breeders about the ALMS1 gene and its connection to hypertrophic cardiomyopathy (HCM) in Sphynx cats. However, some misunderstandings have arisen, particularly in interpreting the clinical data from a recent study.
The study focused on a relatively small sample of 55 Sphynx cats. While the data offers valuable insights, it’s important to note that conclusions drawn from such a limited sample should be viewed cautiously. Additionally, since HCM is an age-dependent disease, it may not fully develop in all cases during the short follow-up period (just under two years).
Of the cats diagnosed with HCM, 22.7% did not carry the ALMS1 variant, while 76.2% did—either homozygous (13.6%) or heterozygous (63.6%). Despite this, researchers concluded that, because the majority of the Sphynx population carries this mutation, the ALMS1 variant likely has nothing to do with causing HCM.
This conclusion, however, is nothing new. The fact that the majority of Sphynx cats carry this mutation has been well-known for years, as shown in earlier studies. What is new in this study is that, for the first time, researchers have decided to make this mutation irrelevant to HCM due to the widespread nature of the variant.
As a result, some breeders have been advising others to stop ALMS1 testing, suggesting it’s no longer necessary and that efforts should focus on heart scans and outcrossing. This interpretation can lead to misunderstandings. While not every cat with HCM has the ALMS1 variant, a significant majority do, suggesting that this gene could still play a role.
Moreover, no research has ever suggested that ALMS1 alone causes HCM. Genetic conditions like HCM are complex, influenced by multiple genes and environmental factors. It’s important to consider this complexity rather than drawing conclusions from incomplete interpretations.
The Importance of Genetic Testing in Breeding
As a contrast to the recent study, I came across an insightful paper titled “Genetic Basis of Hypertrophic Cardiomyopathy in Cats” by Dr. Arkadiusz Grzeczka, Dr. Szymon Graczyk, Dr. Robert Pasławski, and Prof. Urszula Pasławska, published in Current Issues in Molecular Biology (August 2024). This research explores genetic mutations associated with HCM, particularly the ALMS1 gene in Sphynx cats.
According to Dr. Grzeczka, various mutations of the ALMS1 gene have been repeatedly linked to the thickening of the left ventricular wall—a key feature of HCM. Interestingly, homozygous ALMS1 mutations (two copies of the mutation) are found predominantly in Sphynx cats and similar breeds like Devon Rex. However, the gene’s widespread presence complicates decisions about its role in HCM. Dr. Grzeczka noted:
“Whether it’s worth testing for these mutations is difficult to answer, as they are widely spread in the cat population, which may indicate a predisposition to HCM in these cats.”
He also highlighted that ALMS1 mutations are found in humans and are sometimes linked to dilated cardiomyopathy, a condition more commonly diagnosed in dogs. This cross-species connection underscores the evolutionary importance of these mechanisms and their potential role in heart diseases.
Prof. Pasławska offered further insights into the importance of genetic testing and breeding decisions. She emphasized:
“Nevertheless, I believe it is worth genetically testing cats and selecting those that are free from suspicious genes for breeding. Why the results in the New Zealand population turned out differently? I don’t know.”
This perspective reflects a forward-thinking approach to breeding, where the goal is not just to avoid issues now but to prevent potential health problems in the future. Combining genetic testing with regular heart scans provides a comprehensive strategy for managing HCM risk and safeguarding the breed’s health.
Ki-67 and HCM Management
In addition to ALMS1, Prof. Pasławska shared valuable information about Ki-67, a nuclear protein linked to cell proliferation. She explained:
“Since it controls proliferation, it is a convenient marker for the intensity of cell growth. It has been shown that HCM is associated with increased cell growth. However, Ki-67 should not be regarded as a marker of hypertrophy, as its increase is also observed in cancer and during regenerative processes.”
She emphasized that high levels of Ki-67 in HCM cases are an important marker for veterinarians, supporting the use of anti-proliferative therapies. Prof. Pasławska has used these therapies for six years with satisfactory results but cautioned that, like HCM itself, the therapy is not always effective for every cat.
Why Testing Matters
HCM (Hypertrophic Cardiomyopathy) is a complex disease with a genetic component, often influenced by mutations like those found in the ALMS1 gene. Misrepresenting autosomal dominant mutations, such as claiming a single copy is harmless “carrier status,” contradicts well-established science. Even one copy of a dominant mutation can increase the risk of disease. Ignoring this fact or failing to educate buyers accurately not only jeopardizes the health of the breed but also undermines the trust buyers place in breeders.
Sadly, there are cases where breeders have avoided genetic testing altogether or bred cats known to carry mutations associated with HCM, dismissing these risks entirely. Skipping heart scans or other necessary health screenings further compounds the problem. Worse, some justify this by claiming that these tests are inaccessible or that referrals are impossible to obtain in Scotland . In reality, these screenings are widely available, including in the UK, and referrals from veterinarians are not an issue. The real challenge often lies in cost, and avoiding these tests raises questions about whether profit is being prioritised over the health and welfare of the cats.
Transparency and Responsibility
Ethical breeding is not just about producing kittens but about ensuring their health, well-being, and the long-term sustainability of the breed. Comprehensive health testing, including genetic test & heart scans for HCM, should be standard practice. Arguing against these measures, particularly for financial reasons, reflects poorly on any breeder’s commitment to their cats.
Setting the Standard
My approach has always been guided by transparency and responsibility. I combine genetic testing with regular health screenings to ensure my cats are as healthy as possible before breeding. This isn’t about doing the minimum—it’s about setting a standard for ethical breeding and prioritising the well-being of my cats above all else.
Ultimately, our actions speak louder than words. While some may choose to focus on shortcuts, I remain committed to raising the bar and doing what’s best for the breed.
Conclusion
While genetic testing for ALMS1 may not provide all the answers, its prevalence suggests it remains an important factor in understanding the breed’s predisposition to HCM. Both Dr. Grzeczka and Prof. Pasławska agree that genetic testing combined with heart scans allows breeders to make informed decisions and advance research into feline health.
As a breeder, our commitment remains steadfast:
• We will continue to test for the ALMS1 variant to contribute valuable data for research and scan the heart our cats annually.
• We prioritize transparency and provide early warnings to buyers about potential health risks.
• Most importantly, all our cats are free from the ALMS1 mutation, ensuring the best possible foundation for the breed’s future.
If you are conducting genetic testing for ALMS1 or have insights into feline genetic health, feel free to connect. Together, we can advance understanding and improve outcomes for the breed.
#HypertrophicCardiomyopathy #HCMResearch #CatGenetics #FelineHealth #GeneticTesting #VeterinaryScience #BreederCommunity #CatBreedingEthics #ResponsibleBreeding #SphynxCatLovers #HeartHealth #FelineCardiology #AnimalResearch #PetHealthMatters #VetLife #ALMS1Awareness #Ki67 #FelineGenetics #CatDNA #HealthyBreeding #PetScience
댓글