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Genetic Testing - More Harm than Good?

Posted on March 3, 2014 at 2:10 AM
(Warning: Shocking Information to Follow).

Yes, genetic research into feline diseases is a good cause, but I propose that funds so expensed are better spent elsewhere. Sounds crazy, right? So, why would I say this? 

1. Often the research finds nothing. Siberian breeders raised 10,000 USD in just over two months to fund Dr Meurs to look for a Siberian HCM gene. None was found.


2. People think the breed investigating the problem HAS the problem and then pet buyers then avoid the breed. Breeders doing the right thing (genetic research) can inadvertantly lead the uninformed to state that the breed HAS that problem. This happened to Siberians who are now said to be "one of the breeds with HCM problems."  While it is true that lines crossed to Maine Coons, Ragdolls, Himalayans, and Persians inherited more than large size, golden coats, and extra long fur may have also added the health problems of PKD and HCM; while those early lines crossed to Abyssinians and Somalis may have inherited more than ticking and picked up PK deficiency and PRA, Siberians as a natural breed only recently brought into the fancy are remarkably disease free if one is importing foundation lines from Siberia and eastern Russia.


3. Well intentioned breeders believe that by testing for that one genetic mutation their lines are free of that genetic disease.  Not true!! Instead even breeds with identified PKD or HCM mutations STILL need to test with board certified Veterinary Small Animal Internal Medicine (SAIM) or Cardiologists. The mutation is for *one* type of that disease. Even in Persians there is PKD2 that has not yet been identified so testing clear of PKD1 only means that the Persian does not have THAT specific genetic mutation. It does NOT mean that the Persian does not have PKD!! I will state that again - being PKD 1 negative is NOT the same as being PKD negative. The cat STILL needs to be sonographed and diagnosed negative by a Board Certified Small Animal Internal Medicine Veterinarian.

     HCM: Painful and deadly.

4. People think affected cats are "carriers." Since breeders are led to believe their lines are negative there is lots of finger pointing when a PKD kitten is born to "tested negative" parents. Or breeders think that a P/N test means that their Persian is only a "carrier" of PKD and so it is OK to breed it. FALSE! The cat *is* sick with PKD (whether it is showing signs or not) and can pass PKD to any offspring (50-50 statistical odds for **Each** kitten born to inherit PKD from a P/N cat. Just because the affected cat "can" have a negative kitten does not mean it is acceptable for the affected cat to remain in a breeding program. 
                         PKD: It isn't pretty.

5. Using excuse that genetic diversity demands breeding affected cats is balderdash. Cats are cats! Just because some breeds have been in the fancy longer than others doesn't mean there is any justification for breeding affected (positive) cats. Genetic diversity is awesomely simple to obtain. Simply search for domestic cats with the traits one wants in the breed and use those domestic cats for breed diversity. Yes, one will have to select hard for type - especially with extreme breeds - but one is diversifying the breed. Yes those cats might have some unknown disease we can't test for or even know about yet - but so can any cat in one's own breed... if it's unknown by definition we do not know about it... 


So what *should* breeders do? Instead of fund raising for genetic testing, might I suggest the radical concept of fund raising to provide reduced sonographic-testing? Testing this way can rule a disease negative or positive. It doesn't just rule in or out *one* genetic varriation of a disease. For instance, a disease like PKD is fabulous - it can be sonographed for (by a specialist) and then ruled in or out. Unfortunately HCM needs to be tested for throughout a breeding cat's life. Save money and get even more cats tested by working with SAIM instead of a Cardiologist. A small animal intenal medicine board cetified veterinarian can test for both kidney and heart disease at the same examination.  This reduces travel costs, exam costs, and stresses on your cats.

Categories: Genetics, Health & Disease, Advice