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Common Health Problems Affecting the Maine Coon Cat Breed.

It’s never a nice thing to think about your pet becoming unwell. As a purebred cat it owner it is important that you make yourself aware of the potential diseases that your feline friend may be susceptible to. Through years of Maine coon breeding it was inevitable that certain genetic issues were going to crop up and therefore it is important that these conditions are screened for.

In general, the Maine coon is a very sturdy breed of cat. There are however some specific genetic conditions that every Maine coon owner needs to be aware of. These medical conditions need to be discussed when adopting a Maine coon, especially when getting a kitten from a breeder. These potential conditions will also have an implication when looking for a pet insurance policy for your Maine coon.

The three most commonly known genetic conditions affecting Maine coons are hip dysplasia, spinal muscular atrophy and hypertrophic cardiomyopathy. There are also several other conditions known to affect Maine coons more frequently than other breeds of cat.

Also remember that your Maine coon will be susceptible to all of the normal illnesses known to affect domestic cats in addition to these specific genetic conditions. Don’t let this scare you though, as with proper screening, vaccinations and responsible care your Maine coon will likely live a long and healthy life. It’s always better to know what to look out for just in case.

First of all, let’s look at the genetic conditions known to affect the Maine coon breed.

Hypertrophic Cardiomyopathy

What is it?

This is condition characterised by thickening of the heart muscle. It is a genetic condition mainly affecting older, male cats. Hypertrophic cardiomyopathy (HCM) is the most common heart condition found in all breeds of domestic cat but even more so in the Maine coon breed. In a multi-national study it was found that 34% of all Maine coon cats carry a gene which could lead to the potential development of HCM (Fries et al 2008).

How is it diagnosed?

In the early stages of the condition there will often be no obvious symptoms. Diagnosis is often an incidental finding by a vet when examining a Maine coon for another reason. For example, they may discover a heart murmur or an abnormal heart rhythm. The condition may also be diagnosed on routine screening by echocardiography. The is a special type of cardiac ultrasound scan performed in breeding pairs to ensure that they have not developed the condition between litters of Kittens.

A genetic test is available for HCM however this test only looks at one specific gene. There are a number of different genetic abnormalities known to cause HCM in Maine coons for which there is no test available. Therefore, unfortunately many Maine coons go on to develop HCM despite having negative result on genetic testing.

HCM will often show no symptoms and the first sign of it can unfortunately be sudden death. Other signs that your Maine coon may be affect are if they are particularly lethargic, having trouble breathing or off their food.

How is it treated?

Treatment requires regular medication given in the form of a liquid. This medication is known as a diuretic, meaning that it removes excess fluid that is building up in the circulation. The fluid is offloaded by increasing the work of the kidneys, meaning that the Maine coon will need to urinate more frequently. This medication can slow the progression of the condition but it will not cure it. Unfortunately, as the condition progresses heart failure is inevitable, the symptoms of which can be extremely distressing for a cat.

For more detailed information on HCM in Maine coons, please see the Universities Federation for Animal Welfare website.

Hip Dysplasia

What is it?

This is a hereditary condition where affecting the integrity of the hip socket. A study by the Orthopaedic Foundation of Animals (OFA) found that almost 25% of Maine coon cats were registered as having hip dysplasia.

Hip dysplasia occurs due to stress on the joints caused by the large size of an animal, therefore it is more commonly seen in dogs than cats. With Maine Coons being one of the larger domestic cat species it is something that pet owners should make themselves aware of.

How is it diagnosed?

There are varying degrees of severity. In mild cases it may not cause any pain and therefore it may not even be apparent that your Maine coon has hip dysplasia. In more severe cases it can present as limpness or lameness.

Breeding pairs are screened for hip dysplasia using ultrasound scanning. Hips are graded as either being normal, borderline or dysplastic. A hip that has been deemed dysplastic will then be further graded as having either mild, moderate or severe dysplasia. In some countries, Maine coons graded 1 (mild dysplasia) can still be included in breeding programmes, as long as they are bred with a Maine coon who has been graded as normal.

How is it treated?

Treatment will depend on the size and age of the cat as well as the severity of the joint dysplasia. Weight management is important aspect of treatment as being overweight will put undue stress on a joint that is already suffering.

Surgery is an option in severe cases and there are several options for the type of operation that can be carried out and these depend on the age of the cat. For Maine coons under the age of 6 months a juvenile pubic symphysiodesis is performed. This procedure creates increased stability by fusing part of the pelvis together. Another option for cats under the age of 1 year is a triple pelvic osteotomy (TPO) to rotate the hip socket. In older cats the preferred option is a total hip replacement. Finally, for cats who have good hip musculature and for whatever reason cannot undergo a total hip replacement then an excision arthroplasty is performed to remove the ball of the hip joint.  

Spinal Muscular Atrophy

What is it?

This neurodegenerative disorder is a genetic condition which causes death of the neurons which control movement of the trunk and limbs. Spinal Muscular Atrophy (SMA) is caused by a deletion of genes found on chromosome 1. SMA comes in three types (I-III) which had different degrees of severity varying from mild weakness in adulthood to a type which is lethal in infancy.

How is it diagnosed?

Kittens with the condition will first shows signs at around 3-4 months of age. By the age of 6 months progression of the disease will lead to the inability to jump up onto furniture.

An affected kitten will have inherited a defective gene from both of its parents. The parents will likely show no outwards signs of the disease, this is because they are simply carriers of the gene for the condition. This mode of gene transmission means that the condition is known as an autosomal recessive condition.

In order for a kitten to develop the condition it must have inherited a defective gene from both of their parents. If they only inherit the gene from one parent then they will become a carrier. This means that they will not develop the condition themselves but they will risk passing on the gene to their offspring. The inheritance of these genes is explained in the table below:

Mother Chromosome Positive
Mother Chromosome Negative
Father Chromosome Positive Kitten has the gene and will develop SMA Kitten carries gene but does not develop condition themselves
Father Chromosome Negative Kitten carries gene but does not develop condition themselves Kitten does not have SMA gene and cannot pass it on

How is it treated?

The condition is not treatable but Maine coons with this condition often lives happy lives as indoor cats.

Patellar Luxation

What is it?

In this condition the patella (knee cap) slides out of place and around to one side. This is due to a knee joint which has not formed properly. It is common in many types of cats but more common in the Maine coon breed.

How is it diagnosed?

A cat suffering from this condition will present with progressive limpness or lameness. They may not show any signs until the condition is well advanced. It can be diagnosed by X-ray imaging.

How is it treated?

Early detection is key in treating this condition. If only one leg if affected then simple medication may suffice however if the condition is more sever then your vet may recommend surgery in order to fix the problem. Having patellar luxation will put your furry friend at a higher risk of developing arthritis in the future.

Polycycstic Kidney Disease

What is it?

Polycystic kidney disease (PKD) is a hereditary condition in which cysts form on the kidneys. It is most commonly seen in the Persian cat breed, followed by the British Shorthair and Ragdoll breeds. It is also not uncommon in Maine coons and because of this genetic testing is commonly performed by breeders.

Kittens are born with small fluid-filled sacs on the kidneys which slowly grow over time. As they become larger these cysts will cause obstruction, preventing the normal tissue of the kidneys from functioning properly.

How is it diagnosed?

Although it is possible to see kidney cysts on ultrasound scanning from the age of 8 months, the cysts grow only gradually in size and therefore it is rare that symptoms will develop before the age of 3 years. The symptoms your Maine coon exhibits will depend on the size and positioning of the cysts. These factors determine the impact of the condition on their kidney function.

The symptoms of polycystic kidney disease are vague. In the beginning it may just be that the cat seems out of sorts, not eating as much as usual and may have changes to their fur coat; it may just appear less shiny and healthy than usual. As the cysts increase in size frequent urination may become a predominant feature. Symptoms of PKD include:

  • Poor appetite
  • Weight loss
  • Frequent urination
  • Bad breath
  • Loss of shiny fur coat
  • Lethargy
  • Vomiting
  • Dehydration
  • Pale mucous membranes (inside of the mouth and around the eyes)
  • Enlarged, lumpy kidneys

Polycystic kidney disease is caused by the PKD1 gene. A genetic test for the condition is available but this will only tell you if the cat has a genetic predisposition for developing the condition. PKD is inherited in an autosomal dominant fashion, meaning that if a kitten receives a defective gene from one of their parents then they are at risk of developing the condition. The table below explains how the condition is inherited when one parent has the gene for the condition:

Mother Chromosome Positive
Mother Chromosome Negative
Father Chromosome Negative
Kitten has the gene and is at risk of PKD
Kitten does not have gene and is not at risk of PKD
Father Chromosome Negative
Kitten has the gene and is at risk of PKD
Kitten does not have gene and is not at risk of PKD

Genetic testing does not give any information about the size or the number of cysts present on the kidneys. This can be determined by a simple ultrasound scan. In general cats do not need to be sedated for this investigation as long as they can be kept calm. It is a non-invasive scan which does not cause any pain. With Maine coons their fur is often too long for an ultrasound to be carried out effectively therefore it is likely that a small area of fur will need to be shaved in order to carry out the scan.

If PKD is a concern then it is likely your veterinarian will want to perform some blood tests. These tests will look at the health of the kidneys in terms of their ability to function. From this your veterinarian will be able to tell if your coon’s kidneys are filtering toxin from the body effectively and also if your Maine coon is becoming anaemic (a common result of kidney failure).

How is it treated?

Cats with small cysts may never show any signs of the condition. In these cases nothing needs to be done.

There is no treatment for PKD but Maine coons found to have the condition will be monitored regularly to check that their kidney function is stable. If kidney function is found to be dropping then medication is available to slow the progression of kidney failure. If a particularly large cyst is identified then aspiration of the cyst is an option. This involve using a fine needle to remove the fluid from within the cyst. Again this depends on the size and the positioning of the cyst.

Because this is a slowly progressing disease many Maine coons will live until over the age of 10 years even with the condition.

Click to the next page for more health conditions affecting Maine coons.


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