Hypertrophic Cardiomyopathy
It has been studied in Main Coons, but it is by no means confined to that breed
The genetic basis for HCM is under study. In humans, 9 principal genes have been identified, along with about nine times that number of variants.
A study by Dr Kittleson has identified a dominant gene with a variable expressivity in one group of Maine Coon cats, but in some other cases, a traceable dominant pattern of inheritance is not obvious.
With HCM, parts of the heart thicken which impairs their ability to flex. This means that the heart has to work harder and leads to enlargement of heart chambers and the collection of fluid around the heart. This can restrict the lungs.
HCM unfortunately is progressive and incurable, but treatment can slow its development and make the cat more comfortable.
HCM can be diagnosed by ultrasound scanning by an experienced ultrasonographer. The age when HCM can first be diagnosed is variable, but after two years of age it will probably make its appearance if it is going to develop, but this is not guaranteed.
A negative scan is no guaranttee that a cat has not inherited HCM.
Depending on the rate of development and the medical care given, a cat with HCM can live happily for several years. Serious complications are heart attacks and thrombosis, both of which are likely to be fatal.
There is no genetic test for HCM, and until the genetics of HCM in cats are better understood, it is impossible to eliminate the disease in any group or breed.
The advice being commonly given at present is not to use known HCM positive cats for breeding, and to test existing progeny of positives.
The development of HCM can appear to skip several generations, and so probably could be inherited from cats which are thought to be negative. Eliminating breeding lines which could possibly be implicated may seriously damage a breed genepool while doing little towards eliminating the disease.
What is needed above all is data, and breeders willing to report HCM positive cats confidentially. It is hoped a confidential database of cats positive for HCM can be set up and be made available to researchers.
HCM Links
A very comprehensive web site with a lot of information and many links.
The paper presented by Mark D. Kittleson, DVM, PhD; Kathryn M. Meurs, DVM, PhD; Marcia J. Munro, BA; Judith A. Kittleson, RN, MS; Si-Kwang Liu, DVM, PhD; Paul D. Pion, DVM; Jeffrey A. Towbin, MD
The Abstract
Knowledge about human heart disease spurs scientists to study cats, by Valerie Hedden.
A description of various diseases which cause changes in the heart muscle.
"The following is a compilation of information on the disease for veterinarians and pet owners, including a list of other HCM Internet resources. (Standard disclaimer -- I'm not a vet and this is not medical advice.)"
A site dedicated to educate and inform the Turkish Angora breeding community of HCM (Feline Hypertrophic Cardiomyopathy), a heart muscle disease.
Diagrams and details of the effects of the disease.
Case 8: Ultrasound images of a two-year-old Maine Coon cat presented for cardiac evaluation for possible hypertrophic cardiomyopathy.