ALL Sphynx breeders of the world should be aware of the high risk of HCM in their breeding cats and in the kittens they produce.  

In an attempt mitigate HCM in our breeding program and in the Sphynx breed itself, WE FEEL that all Sphynx cats that are part of a breeding program should be tested at age 1 and then ever year thereafter throughout their life; even after retirement.  Scanning for HCM will allow you to assess risk for individual cats and will help identify carriers of the genetic mutation, therefore allowing you mitigate disease from future lines.

Because HCM carriers are in the pedigrees of all Sphynx, it is very important to breed cautiously.  

How Do We Breed Cautiously?

Carefully study breed-wide pedigrees.  A high inbreeding co-efficient, with HCM prevalent in the lines can be very risky. 
Carefully study HCM data published in the Sphynx HCM Database in order to determine which lines are an are not producing HCM.
Test all breeding cats annually; even after retirement.  Submit all HCM data to the Sphynx HCM Database.
Although there may be other situations outside the scope of normal breeding circumstances, we use the following guidelines.  

Normal Heart:
Cats with a normal heart status according to a echo-cardiogram and without any close relatives* diagnosed with HCM can be used in breeding.

Diagnosed with HCM:
Cats diagnosed with HCM of any degree should not be used in breeding.

Equivocal:
Cats with inconclusive or borderline heart health status and with or without any close relatives* is not recommended to use for breeding until normal heart health is conclusively verified. Echo-cardiograms should subsequently be done every 6 months.  If the cat remains equivocal the cat should not be used in breeding until he/she receives a clear scan. 

Close Relatives:
Parents - If either parent has been diagnosed with HCM, in general, the cat should not be used for breeding.  

However, careful consideration is given if the parent is over 6 and has not produced any other HCM offspring. Because not all HCM is genetic, careful analysis and care should be given prior to cutting off a line. In the situation of an HCM parent, our practice is to advise all adopters and the extend the guarantee for two additional years.

A breeding cat in this situation should only be mated to a risk-free partner (has no close relatives that have been diagnosed with HCM). 

Siblings - If a full sibling has been diagnosed with HCM, and the heart is normal on the cat itself, it is not generally recommended for a cat to be used in a breeding program.

However, careful consideration is given if the sibling is over 6 and has not produced any other HCM offspring. Because not all HCM is genetic, careful analysis and care should be given prior to cutting off a line. In the situation of an HCM sibling, our practice is to advise all adopters and the extend the guarantee for two additional years.

A breeding cat in this situation should only be mated to a risk-free partner (has no close relatives that have been diagnosed with HCM). 

Other relatives - If other relatives have been diagnosed with HCM, and the heart is normal on the cat itself, it is not recommended to be used in a breeding program until the cat is scanning clear over the age of 2-3. 

A breeding cat in this situation will get a birth control implant until the age of 2 or 3 and then will only be mated to a risk-free partner (has no close relatives that have been diagnosed with HCM). 

*Other notes:
In my experience, it "appears" that HCM affects males more often than females.
In my experience, it "appears" that "incomplete penetration" is more common in females.
Sphynx with hypertension, hyperthyroidism and hypersomatotropism can cause "non-genetic" HCM.  Therefore, appropriate tests should be performed.

What About the HCM DNA Test Developed by NCSU?

In my opinion, the HCM DNA test developed by North Carolina State University is immaterial at this point, therefore, I do not rely on the results to further my breeding program.  I rely 100% on annual HCM echocardiagrams of my breeding cats and their ancestors. 

  • There have been numerous accounts of homozygous Sphynx that have scanned clear for HCM at very old ages and have produced zero HCM offspring.  Because of this, I do not trust that a cat homozygous positive for the ALMS1 mutation is NOT SAFE to breed. Eliminating these cats based on the DNA test results would be catastrophic for the future of the breed.

  • There have been numerous accounts of negative/negative Sphynx that have scanned positive for HCM and have numerous HCM offspring.  Because of this, I do not trust that a cat negative for the ALMS1 mutation is a safe cat to breed.

  • Only non-Sphynx HCM-negative cats were used in the NCSU university study. 

I encourage all breeders and owners however, to study the original research done at North Carolina Statue University, as well as subsequent research to determine if we should be relying on these DNA tests over HCM scanning.  Below are resources.

 

JS Social Tabs Slider