HCM in Sphynx
What is HCM?
Hypertrophic Cardiomyopathy – the most common of acquired heart diseases in cats. It is a heart muscle disease where the left ventricle becomes thickened over time. It can happen at any age. It causes the heart to stop functioning as it should which can in turn cause blood clots, and it otherwise affects the structure and functioning of the heart. There is no cure, but the condition can be medicated. Some cats with HCM can live long and happy lives as long as they are medicated. It is a disease also know in humans. Some cats will only have a mild case, whilst others may be severe which may cause death.
Is sphynx the only breed it happens to?
There are many breeds known to be affected by HCM, including domestic cats, Maine Coons, Ragdolls, Norwegian Forest Cat, Siberian, just to name a few
Why should that mean anything to me?
With sphynx, HCM is thought to be genetic, although it can skip generations and turn up at any time. If an ancestor of a sphynx has been diagnosed for HCM, there is a disposition for the risk, but it does not mean the cat will develop HCM.
How can you test for it?
We recommend that all sphynx are tested. Due to the nature of the disease, you cannot test until they are 12 months old. We recommend this for all breeding cats and then annually. For all pet sphynx we recommend testing at least every 18 months from 12 months of age. Testing can vary in cost and is expensive, but well worthwhile.
- There is no value in dna testing sphynx for HCM as there is no dna test for sphynx (there is a dna test for ragdolls and for one of the two known genes in Maine Coon)
- Pro-BNP Blood test may indicate an issue with the heart, but it is not HCM specific. There is also a large error factor when using this test to diagnose HCM in sphynx
- Echocardiogram – this is the gold standard for testing sphynx for HCM, and should be done by a feline cardiologist, not a general vet. There are currently five certified feline cardiologist in Australia. When purchasing a sphynx please ask to see original documentation of HCM results and if not possible, then ask for authority to contact the specialist to verify results.
Dr Fiona Campbell BVSc(Hons), MANZCVS, PhD, Dip ACVIM (Carrara, QLD) www.vss.net.au
Dr Brad Gavaghan BVSc MACVSc FACVSc (Brisbane, QLD) www.vss.net.au
Dr Richard Woolley BVETMed, Dop ECVIM-CA, MRCVS (Victoria) www.cprvictoria.com.au
Dr Rita Singh BSC,BVNS(Hons) Dip Vet Clin Stud, FACVSc, Dip AVCIM (Sydney) www.sashvets.com
Dr Niel Beijerink DVM, PhD, Dip ECVIM-CA (Sydney) www.sydney.edu.au/vetscience
What does it mean for my nakid?
When you are considering buying a sphynx, please verify the breeders stance on testing and ask for copies of current documentation or guarantees against HCM. Also ask for a copy of the pedigree and use the following websites to investigate the known incidence of HCM in those pedigrees before purchasing (there are more website available, but not all breeders list results).
The HCM testing ultrasounds only prove at that time that the cat does not have hcm.
This is true, much the same way that when a human tests negative for any virus or disease they could test positive at any time afterwards if predisposed or exposed. However measurement taken by the cardiologist give a good indication of what will happen in the next 12 months, particularly when compared to previous results from the same cat.
Avoid inbreeding as that is a factor in hcm.
Partially true – if ancestors carry hcm it is more likely that offspring will carry it. However in sphynx this is a big unknown at this time as it can skip through generations and no pattern or gene have been identified.
Previous breeders of the same lines have scanned and have no positive results, so there is no need to test.
False. Breeders who don’t test can easily they have no hcm as if there is no testing there can be no identification. Also many breeders who do test do not advertise that they have had a positive cat.
An hcm scan per cat is $330 or more and is not a true indication whether the cat will develop for hcm.
False – an ultrasound hcm scan annually is currently the gold standard for testing. The test works by measuring tissues and comparing to the standard for HCM diagnosis as well as the cats previous scans, this is the best indicative test that currently exists at this time. Whilst is can cost that much per cat per year, often discounted rates may be available.
Until a DNA test is developed HCM scanning by any other means is a waste of money.
False – when cats are tested regularly and the tests (with pedigrees) submitted to research organisations no matter what the result, these worldwide results can be researched together and hopefully a dna test developed and a pattern of affection identified. For future owners of breeds that suffer HCM, this should be compulsory for current owners.
Do breeders guarantee their kittens against hcm
Some provide a warranty. Until the exact cause and gene are known it is impossible for any breeder to predict what will be affected – but what responsible breeders do will be to provide you a warranty against HCM – it does require some actions required by the owner and also provides actions that the breeder will take if a cat is diagnosed as HCM positive.
Some breeders use cats whose ancestors have had hcm
Yes, this is true for all sphynx. Particularly when the sphynx breed was first identified in the 1960’s and HCM testing was not done. It was later found in older cats and this is how it was identified as an issue – particularly when those cats had bred for a number of years. It is possible that all sphynx have HCM cats in their pedigrees – in older generations. It did not help that outcrossing was done with other HCM affected breeds such as Devon Rex and Ragdolls. If a current breeding cat is diagnosed with HCM the responsible breeder will desex the cat immediately, notify all buyers of those lines and have the cat assessed for treatment
Pet owners think that by hcm scanning that means that their kittens are safe
False. If the buyer is not already aware, a good breeder advises them on all aspects of HCM
HCM is not necessarily a death sentence. Many different breeds are affected including domestic cats. Whilst there is no cure, there are different medications available to help to control the disease. There are HCM affected cats who have lived to 15+ years and have passed from other causes.