Fewer things have caused such controversy among Maine Coon breeders. Our screening choices are only the opinion of the writer. There is, at this time, a strong division of opinion as to the correct course to follow.
Some facts:
HCM (Hypertrophic Cardiomyopathy) is an inherited disease of the heart, which causes the muscle to thicken and become an ineffective pump. A cat with active disease is at great risk for heart failure, and sudden death. Another not uncommon outcome of HCM is a saddle thrombus, which is a blood clot that becomes lodged in the lower spine and prevents blood from reaching the lower extremities, resulting in paralysis of the back legs. It's extremely painful and frightening for the cat, and most do not survive. Those that do survive are at high risk for reoccurrence.
HCM is autosomal dominant, which means that at least one parent of an affected cat also has the disease. HCM is expressed with incomplete penetrence, which means that that the age in which affected cats become symptomatic varies widely.
HCM has been identified in many breeds of cats, including random bred (mutts).
There are viable treatment options for HCM that will increase life expectancy, allow excellent quality of life, and slow or halt the progression of clinical symptoms. There are cases where heart health has *improved* with the proper medication. This is not to say that HCM is not an extremely serious health condition, but to give hope to those whose pets are affected.
Some conjecture:
Maine Coon breeders have long been proactive in seeking to eliminate this disease from our breed, and unfortunately, this has caused some veterinarians to conclude that Maine Coons have a higher instance of disease than other breeds of cats. This has not been proven. It stands to reason that evaluating large numbers of related animals of any breed for a particular inherited issue would result in a higher number of cases in that breed being documented. We are saddened that this healthy and robust breed of cat is becoming so strongly linked to the devastating disease of hypertrophic cardiomyopathy.
Current screening methods:
The gold standard for identifying clinical HCM is a cardiosonogram done by a Board Certified Cardiologist. However, a normal cardiosonogram is not predictive of future disease, and therefore should be repeated at regular intervals.
Recently, a DNA test has been developed that identifies a marker associated with HCM in the Maine Coon Cat. This is an ongoing research project, and at this time we do not know exactly what this marker means to an individual cat. The camp is adamantly divided on whether cats who carry the marker should be used in breeding programs. Here are a couple of reasons why there is a division:
It was originally suspected that any cat that carried the marker would die of HCM. While this may still prove to be the case, there is one known cat who, at 15 years of age, carries the marker and does not show signs of HCM on cardiosonogram. He is found in many pedigrees and is not suspected of producing cats with HCM.
There are cats who have confirmed clinical HCM that do not have the marker.
These things tell us that the marker does not point to the only gene responsible for the disease.
And, unfortunately, there are a few cases that we are aware of where, due to human error, test results have been incorrectly reported. Some of the results didn't make sense given the history of the cats involved, and when rechecked, different results were confirmed. We are assured that these cases are extremely rare, however, since there is a cost to the breeder for each test, no one is rechecking negative results. We really don't know how widespread errors are.
This research is very important and must be continued. However, we do not feel that enough is known about how the marker correlates to clinical disease at this time. Some share our opinion, others don't. That's perfectly ok with us and we will not debate the topic. We prefer the wait and see approach.
Lastly, a purely unscientific screening method is to know the pedigree of the cats involved. Long time breeders have the advantage to some extent, as we remember these cats in the 4th, 5th and earlier generations and in many cases we are aware of health history by virtue of osmosis of the cat fancy. We also ask the folks who own kittens from our cats to please keep us aware of any significant health changes in their cats. This is not a totally reliable method, of course, but it does figure into some of the decisions that we, personally, make.
Our experience and our policy:
I have two known affected cats in twenty years while breeding under the name of Rocquoone Maine Coons. Both were males that I brought in as outcrosses to the lines I've worked with for many years. One did not sire, but the other was briefly used in my program. Both of these cats previously screened clear of HCM by boarded veterinary cardiologists - which underscores the need for repeated cardiosonograms and illustrates the value of these cardiosonograms as a "place in time" methodology.
DamnYnke relies on a combination of sources of information to make our breeding decisions. We recognize that we are dealing with living creatures and do our best to mitigate the opportunities for disease. While we hope that we never have to invoke it, we offer a health guarantee with a replacement clause. Still, we strive to produce animals that will never bring that kind of heartache to their people. We feel that this is the best that anyone can realistically offer.
email us