Common Serious Health Issues of the Maine Coon
As a responsible pet buyer or breeder, it is important to know the most common problems and health issues in a Maine Coon. This will help you know what to look for and what to ask about when purchasing a Maine Coon kitten whether as a pet to join the family or a potential breeder for your breeding program.
As pet owner you can ask the breeder, what testing they do to help reduce these health issues. Please know, however, that even with all the testing in the world, there is never a guarantee your kitten will not develop a health issue in the future. You have to educate yourself on the potential issues and decide if your kitten should develop that in the future, is that something you can live with?
As a breeder, you should also ask the breeder you are considering purchasing from what testing has been done, and then also strive to complete this same testing on all your breeding cats. This will help ensure you are breeding only healthy cats. Know that while not all disease is 100% preventable, it would be absolutely heartbreaking to have a family call you and tell you a cat or kitten passed away from a 100% preventable disease that got through from your cattery.
Listed below are the most common diseases in Maine Coons.
HCM – Hypertrophic Cardiomyopathy
HCM is a heart disease that causes the hearts muscular walls to thicken, which can lead to blood clots, fainting, and congestive heart failure. It is believed that HCM affects approximately 15%1 of all cats, and in Maine Coons specifically, the percentage is estimated to be higher. It is believed that as many as 30% of all Maine Coons2 carry a gene believed to be associated with HCM. However, researchers also believe there are other factors that also contribute to the development of HCM as some cats who have been diagnosed with HCM do not have the common genes known to be associated with HCM. While research is ongoing, for now we have to rely on the tests we have to reduce the possibility of HCM developing in our cats.
Figure 1 – The heart on the left is a normal heart. The one on the right has the thickened muscle associated with HCM. Photo courtesy of cornel.vet.edu3
One thing breeders can do is to genetically test their cats DNA to see if they carry the genes believed to be responsible for HCM. In my belief, this is an absolute minimum that any responsible breeder should do. These tests are not prohibitively expensive and are generally reliable. Every cat will have two genes that could possibly carry the mutation. Basic genetics says the cats get one gene from mom and one gene from dad. So the cat may have zero copies of the gene, one copy of the gene, or two copies of the gene. Any cat with two copies of the gene absolutely should not be part of any breeding program because they have 100% change of passing a copy of the gene to the offspring. It is believed the gene responsible for HCM in Maine Coons displays incomplete dominance. That means that a cat with one copy of the copy is not necessarily guaranteed to develop HCM because the gene may not “penetrate” and develop. But the cats might be at slightly higher risk that a cat that does not carry the gene (1.8 times). However cats with two copies of the gene are 18 times more likely to develop HCM than a cat with zero copies of the gene.5
Another step breeders can do to help prevent HCM is to perform echocardiogram screenings of their cats to see if there is any abnormality in the heart before breeding. Echocardiograms are considered the gold standard in detecting HCM.4 Because many researchers believe there is more at play in the development of HCM than just the known genes that can be tested for right now,breeders can take the extra step of screening hearts of their breeding cats. Echocardiograms are more expensive and should be completed every one to two years for breeding cats. In addition, not every vet has a cardiologist on staff to perform echocardiograms. So breeders would have to drive to a specialist vet. Due to this additional cost and difficulty in finding a local professional, some breeders do not take this step. If the breeder you are considering purchasing from does not perform echocardiograms, you will have to decide if this is something you are willing to accept.
SMA – Spinal Muscular Atrophy
SMA is a loss of motor neurons in the lower spinal cord and atrophy of the muscles in the lower limbs. This disease is characterized by an unsteady gait or walk and can be noticeable in kittens as young as 3 or 4 months.6 The fortunate thing about this disease is that it is not fatal or painful and the cat can live comfortably indoors. But this gene can also be tested genetically. The disease is considered autosomal recessive. That means that the cat or kitten must have two copies of the gene to be affected. If your cat or kitten has only one copy, they will not be affected by this disease. Because this gene can easily be detected via genetic test, we recommend that you ask your breeder if they have tested their cats for this gene.
If you are a breeder and one of your breeding cats carry this gene, you should ensure that you are not breeding to another cat that also carries this gene. As long as you breed to a non-carrier, none of the kittens will ever be affected.
PKD- Polycystic kidney disease
PKD is a disease of the kidney in which the kitten has cysts on its kidney. These cysts can grow in size and multiply until they overwhelm normal kidney function and could lead to kidney failure. These are most prevalent in the Persian breed.7 Obviously, this can be a devastating disease for your cat, but fortunately the gene responsible for this condition can be tested for via genetic testing. The gene for this disease is considered autosomal dominant, meaning only one copy of the gene needs to be present for the condition to develop. Because this gene can easily be detected via genetic test, we recommend that you ask your breeder if they have tested their cats for this gene.
If you are a breeder and one of your breeding cats carry this gene, you should not use that cat for breeding.
PKDef- Pyruvate Kinase Deficiency
Pyruvate Kinase Deficiency is a disorder that causes anemia due to break down of red blood cells. Fortunately the gene responsible for this condition can be tested for via genetic testing. The gene for this disease is considered autosomal recessive. That means that the cat or kitten must have two copies of the gene to be affected. If your cat or kitten has only one copy, they will not be affected by this disease. Because this gene can easily be detected via genetic test, we recommend that you ask your breeder if they have tested their cats for this gene.
If you are a breeder and one of your breeding cats carry this gene, you should ensure that you are not breeding to another cat that also carries this gene. As long as you breed to a non-carrier, none of the kittens will ever be affected.
Hip Dysplasia
Hip dysplasia is a genetically inherited malformation of the ball and socket of the joint that connects the thigh to the hip. It is rare in cats in general. But of all feline cases where it has happened, it is more prevalent in Maine Coons8. This is believed to be because of their large size. If your cat has hip dysplasia, they may have a mild case and not really be affected by it. The treatment may be as simple as keeping them from jumping from high places and ensure they maintain a proper weight. Or it could be severe requiring surgery which could get expensive.
At this time, there is no genetic test for hip dysplasia. The only way to screen for it is to have an X-Ray completed of the hips. One organization who reviews hip X-Rays is OFA, Orthopedic Foundation for Animals. Another organization that reads hip X-Rays is PawPeds. Many breeders use one of these organization’s to read their hip X-Rays and grade their cat’s hips. They have three grades for normal hips and three grades for hips with some sort of hip dysplasia. In the normal range, there is Excellent, Good, and Fair. All three grades are considered normal and can be used in a breeding program. The grades for cats affected to some degree by Hip Dysplasia, are Mild, Moderate, or Severe. Because there is a genetic component to hip dysplasia, if cats with normal hips are bred to cats with normal hips, in theory, all the kittens should have normal hips. However, this is evidence that two animals with Normal hips mated together do have a chance of producing a kitten with hip dysplasia.9. But mating two cats together who both have hip dysplasia have a much higher chance of producing kittens that will be affected by hip dysplasia. So even if your breeder is doing everything they can to prevent hip dysplasia by getting hip X-Rays, and not using cats in their breeding program with hip dysplasia, know there is still a chance your cat or kitten could be affected by it. You have to decide if that is a risk you want to take. You can decrease that risk by asking your breeder if they do screen for hip dysplasia.
Pawpeds has published recommendations for breeding regarding hip dysplasia, you can see the full article here. Essentially the article states, because it is not recommended to make too narrow a selection of the gene pool of Maine Coons at this time, it is recommend that any cat with Mild dysplasia be bred only to a normal cat, and not totally excluded from the breeding program. Due to the various genes involved in hip dysplasia, and the fact that two normal cats can produce kittens with dysplasia; or two cats with hip dysplasia, can produce cats with normal hips, it is recommend to test each generation of breeding cats.
These are the major and most devastating illness/disease your cat can inherit from their parents. There are other common diseases they may acquire, but those are more environmental, meaning they catch them from either other cats they are around or the environment they are in. We will discuss those in a separate article.
Resources-
1. https://cvm.ncsu.edu/nc-state-vet-hospital/small-animal/cardiology/cardiology-feline-hypertrophic-cardiomyopathy/
2. https://cvm.ncsu.edu/nc-state-vet-hospital/small-animal/genetics/submit-dna-testing/nc-state-veterinary-hospital-small-animal-veterinary-genetics-cardiac-health/maine-coon-cat-hypertrophic-cardiomyopathy-hcm/#:~:text=Several%20studies%20indicate%20that%20the,as%20having%20%E2%80%9Cincomplete%20penetrance%E2%80%9D.
3. https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/hypertrophic-cardiomyopathy
4. https://ivcjournal.com/feline-hypertrophic-cardiomyopathy/
5. https://vgl.ucdavis.edu/test/maine-coon-hcm
6. https://vgl.ucdavis.edu/test/maine-coon-sma
7. https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/polycystic-kidney-disease
8. https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/hip-dysplasia
9. https://www.pawpeds.com/cms/index.php/en/health-programmes/hd/info
