What is HCM and HCM in Ragdolls

I have had multiple requests from readers asking for more information about HCM in Ragdolls. They want to know what is HCM and also what to do if your kitty has it.

From another breeder friend, I found out that Sue Shorey of SuPurr Ragdolls and also the current RFCI President has done extensive research on HCM in Ragdolls. So I asked her if she would be so kind to write an article for the site.

Her article is below. Thank you, Sue, for helping all the beautiful Ragdolls with this knowledge!

Hypertrophic cardiomyopathy (HCM) is a heart disease where areas of heart muscle enlarge and thicken. It is the most common heart disease in cats both purebred and domestic and has been found to be inherited from the parents.

When the left ventricle becomes thickened, is unable to fill with a normal volume of blood, it follows that less than a normal amount of blood is pumped out to the body with each heartbeat. If the blood supply to other vital organs is inadequate, the heart rate may increase as the body attempts to compensate which can increase the filling pressure on the left side of the heart and contribute to congestive heart failure.  Signs could be a heart murmur, weight loss, weakness.  A cat could have some, all, or none of these signs.

The left atrium of the heart enlarges due to the increased pressure which can slow blood flow and cause blood clots to form.  Clots dislodge and can become lodged blocking the flow of blood.  Rear leg paralysis can be a result of a clot blocking the branches of arteries that go to the rear legs.

Research was started in 2005 for the Ragdoll breed to try and find a HCM DNA test to determine if a cat was carrying the HCM mutation.  Our breed was lucky enough that Dr. Kate Meurs did just that!  In May of 2007 Dr. Meurs found the MyBPC3R mutation and we now have a DNA test available that anyone can use to be sure that breeders that are being used, or pets that are purchased, are not carrying this one mutation.  Several years ago, a DNA test for Maine Coons was also developed which was a different mutation that was found in a very few Ragdolls. While there may be more mutations found in Ragdolls at some future date, none have been found, to date beyond the two mutations.  A Ragdoll should be tested for both of these mutations to be sure that they are not carrying either of the two known mutations found in cats.

Most, if not all, HCM cases in Ragdolls are caused by a mutation that is inherited from their parents.  A cat can carry one mutation or it can carry two.  It can get one from each parent or it can only get one, etc.  Usually a cat that has inherited two mutations from each parent (homozygous) will have a severe case of HCM.  Those carrying only one mutation (heterozygous) can sometimes have a lesser case but not necessarily!

If you find that your cat has HCM, it is very important to get them an echocardiogram at a certified cardiologist.  They will be able to determine if your cat is expressing the disease (heart is actually showing signs of it) or if they appear healthy the moment and show no signs.  Ones that are expressing the disease can be put on medications that can help lengthen the lifespan of your kitty.  While HCM cannot be cured, there are medications that can really help.  Any kitty found to be carrying an HCM mutation, should be checked periodically by a cardiologist.  A veterinarian cannot always tell if a cat has HCM or not because it can have a heart murmur or not.  A cat with HCM can seem to be acting perfectly normal one day and throw a clot and die the next.

The most important thing for breeders is that they are only breeding with NEGATIVE cats.  If the parents are free of any mutations, then the kittens will be too. Ragdoll cats can die young with carrying just one mutation so it is very important to know the health status of your Ragdoll.  It is up to the pet buyers to be sure that the breeders are breeding with only negative cats and you should ask for proof that testing has been done by proven labs.  The ones I recommend are:

NCSU http://www.cvm.ncsu.edu/vhc/csds/vcgl/index.html (RD & MC testing)

UC Davis http://www.vgl.ucdavis.edu/services/cat/ (RD testing only)

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Hi, I’m Jenny Dean, creator of Floppycats! Ever since my Aunt got the first Ragdoll cat in our family, I have loved the breed. Inspired by my childhood Ragdoll cat, Rags, I created Floppycats to connect, share and inspire other Ragdoll cat lovers around the world,

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  1. Deborah Taylor says:

    Echo, My 7 1/2 year old ragdoll girl has just been diagnosed with Restrictive Cardiomyopathy. (the worst) She had her wellness checkup a few months ago and supposedly everything was perfect. They listened to her heart, no murmur and did a full blood workup on her no problems. I took her in for tummy upset (was worried about a hairball blockage) plus she felt thinner to me and seemed a little finicky with her food. Her left atrium is three times what it is supposed to be and she is on an ACE inhibitor and furosemide, a diuretic to help. I am a wreck, she is my number one precious girl and sleeps by my head/pillow at night, loves belly rubs and follows me everywhere. My heart hurts to think she could throw a clot or experience any pain. I don’t know how much time she has left but my life will be very sad without her. I know they don’t love forever, but this is too young, too soon and very unexpected. 🙁

    1. Deborah Taylor says:

      I meant live forever

    2. I’m so sorry – I hope there are ways to give her longer life expectancy

  2. Lynn Nelson says:

    I’m trying to understand something. Is there a test for a kitten that will tell you if they have this heart problem? I wonder if you can have each kitten tested to know before selling/buying.

    thank you

  3. Pam Ritchie says:

    . We just lost our 12 year old Ragdoll to HCM. We had him tested and he was negative. We know of one of his littermates that produced HCM kittens and she also had been tested negative. so while it is a good thing that breeders are testing their cats for the mutation, they should also be scanning and be aware that there IS more than one mutation. The test even says to be aware that just because your cat has tested negative does not mean he will never have HCM. He just won’t have it due to the found mutation, our boy was on 4 different heart meds and ended up going into kidney failure less than a week after his kidneys were tested as being good. Sure the meds help but they have side effects that can be just as deadly as the heart problem you are trying to treat.

    1. Oh good grief – I am so sorry to read about your loss. Do you have more information – specifics you could list in case someone is googling the medication that they might find your post? Or if you’d be willing, could you do a write-up explaining everything to maybe help another kitty?

  4. cheryl biber says:

    I just got a ragdoll and thought he could not get this disease. Both parents DNA negative. However a cardiologist just explained that it is still possible to get by a mutunt gene or another gene not yet identifi

  5. I just found out my 6 month old kitty has this we are devastated…on medicine and doing ok but so worried I won’t get long with my beautiful pippin

    1. Hi Karen, I am so sorry – if you want, we can post something on Facebook and see if others have insight? Thanks, Jenny

  6. Cathy Sauer says:

    We also lost our beautiful 4 year old Sabrina to this disease. We did not know until too late. One of her symptoms was a raspy cough every now and then, which we thought was asthma. When she went for her annual checkup and we mentioned it, the HCM was discovered. Yes, there are meds, but they only kept her alive 3 months and during that time she repeatedly had her chest cavity drained of fluid. As mentioned in the article, she was acting fine, then threw a clot – very suddenly – was in pain and paralyzed in her back legs as she was rushed to the emergency hosptial that had been treating her. We were unable to save her. It is heartbreaking to have such sweet cats have to endure this terrible disease. Any breeder that has this in their cattery should be ashamed of themselves if perpetuating it. I was in touch with Sue Shorey to report the breeder from whom we got Sabrina – who, by the way, denies having it her cattery, which is in Merritt Island Florida. This breeder also denies there is a test. Shameful.

  7. Thanks a lot about your information. Few days ago, my friends ragdoll cat went heaven because of HCM 🙁
    And her cat’s breeder said, they already testing about HCM (baby’s mom&dad), so baby’s death was coincidence.
    And they had been breeded HCM cat in 2008 so they had have problemed that days, but they claimed HCM test was generalizationed at 2009. So that’s an accident… I can’t believe what they said, so googling webs and find your information..
    thanx a lot.. 🙂

    1. I am sorry to hear about your friends’ cat. That is just horrible and I hope the breeding stops of the cat with HCM.

  8. We lost our sweet Inigo to HCM, thank you for raising awareness of this in ragdolls.

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