# Feline Hip Dysplasia Testing



## BB76 (Sep 9, 2009)

Until very recently, cats were not thought to be affected by hip dysplasia but more cases are now being reported. I am interested to understand how many cat breeders are aware of the condition and have been testing for the genetic defect before breeding? I welcome any comments, views or experiences of the condition.


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## spid (Nov 4, 2008)

I personally have only heard of it in relation to BSH but I have to say I've only heard of three cases and that doesn't a trend make. I didn't know there was a genetic test for it in cats. I'd be interested in seeing where and how they do this.


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## MerlinsMum (Aug 2, 2009)

spid said:


> I'd be interested in seeing where and how they do this.


I hadn't heard of it til this thread either - but my vet-tech friend visited last night and just out of pure curiosity gave my kittens a once-over. I noticed him feeling the bone structure very carefully, though you wouldn't be able to tell HD from that.

Where ther do it, I don't know but I guess any vet that can do HD tests in dogs could do so in cats - it would involve a GA.


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## BB76 (Sep 9, 2009)

Thanks for your reply Spid - make that four cases of BSH and the condition is more common than I thought after dealing with an orthopedic surgeon. Very little on the web which is why I am keen to understand how many breeders are aware of the condition and what tests they really should consider undertaking before breeding. The profile on this MUST be raised, every breeder should be aware of the condition and discuss with their vet before breeding.


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## kozykatz (May 18, 2008)

It's not a problem in all breeds, I've certainly never encountered it in my cats in 20 years of breeding. There isn't a DNA test for it, testing has to be done by x ray. 
I think it's been reported in BSH and Maine Coons, it mainly affects larger breeds as you'd expect.


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## BB76 (Sep 9, 2009)

Sadly the condition does affect a number of breeds beyond those already mentioned which is why it is important for the profile of the condition to be raised so that breeders are aware before any kittens are produced with the disease. It is also important for people considering a kitten to be aware so that they can do more research into the condition and they can speak with the breeder to ensure both parents have been tested and are cleared as not being carriers of the gene. Whilst it is unfortunate that the only test is via an x-ray, it is an important test that should be undertaken as the affect on the cat that is found to have the condition is very distressing. I am yet to find a breeder who is proactively testing for the disease but I very much look forward to hearing from somebody (especially a BSH breeder) who is undertaking such tests.


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## kozykatz (May 18, 2008)

Could you give a reference to back up your statement that HF affects a number of breeds, and that all breeders should be testing their cats?

I would like to read more about this - I consider myself to be pretty much up to date on feline health issues but I've not come across anything to suggest that HD is a major problem like you're suggesting.

thanks in advance



BB76 said:


> Sadly the condition does affect a number of breeds beyond those already mentioned which is why it is important for the profile of the condition to be raised so that breeders are aware before any kittens are produced with the disease. It is also important for people considering a kitten to be aware so that they can do more research into the condition and they can speak with the breeder to ensure both parents have been tested and are cleared as not being carriers of the gene. Whilst it is unfortunate that the only test is via an x-ray, it is an important test that should be undertaken as the affect on the cat that is found to have the condition is very distressing. I am yet to find a breeder who is proactively testing for the disease but I very much look forward to hearing from somebody (especially a BSH breeder) who is undertaking such tests.


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## billyboysmammy (Sep 12, 2009)

I have heard of it, but as yet i wasnt aware that there were any tests available for feline HD?

There are various hip scoring methods available for dogs but i didnt think anything had yet been developed for cats, as it seems the numbers effected seem so low.

On top of that, canine HD there is no genetic test available. It is thought to be polygenic (caused by many genes). This means that a number of different genetic defaults in various combinations go into making a predisposition for HD. Until every gene is identified, and all the combinations are identified, genetic testing for this would be impossible. If the same causes apply in the cat world, then again, there are no genetic tests.

In any large population there will inevitably be sicker and weaker animals. Add to that the BYB, kitten farmers and pet breeders. Who do not breed from good quality stock, do not health test and many times have little knowledge, understanding or caring to ensure the kittens are reared properly. Its fairly obvious that there will be a number of cats and kittens effected by some form of illness or disease thought to have heriditary links.

HD is also more difficult to quantify because of the environmental factors which effect it. Good breeders reccomend restricted excercise for pups from breeds prone to HD, will only breed from healthy tested parents of good hip scores and reccomend pups do not overdo it until they have finished growing. Over excercise, being raiesd on permanently hard floors, running up and down stairs can all contribute to HD. 

I would be very interested to read your research and any you have gathered elsewhere! I would like to see what comparisions can be made between canine and feline HD, and what tests if any are available in the uk.

I have read the the OFA and pennhip are examining HD in cats, but until a scoring system is developed i am not aware of any tests available to breeders, perhaps i'm wrong?


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## lauren001 (Jun 30, 2008)

I found this

Cat Fanciers' Association: Feline Hip Dysplasia

Study was done in 1998, I am not sure if any further studies have been done.


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## dharma66 (Oct 25, 2009)

(EDIT: Whilst I was writing this, lauren001 found the same article in a different place)

The following (quite short) article is interesting:

http://www.winnfelinehealth.org/Pages/Feline_Hip_Dysplasia_Web.pdf

It mentions that the condition has been found in smaller breeds, end explicitly mentions Devon Rex.

It also points out that, as in dogs, there is no genetic test available to detect the fault. Testing in dogs is carried out by XRays being 'graded' by knowledgeable experts. This means that the condition can only ever be detected once it is manifest. If an individual carries one of the several defective genetic combinations that can lead to the condition, but has not yet manifested any unusual tissue deformity, there is simply no way of knowing that.

The article also states that most cats with the condition will not exhibit any discomfort or difficulty. Whilst this is good for the individual, it does suggest tat x-raying before breeding might be good, to ensure that the genetic makeup us not passed on unknowingly. However, that leads us on to the following...

Apparently, x-ray grading in felines is still very much in its infancy, an the article implies that there are only two centres offering this at present.

One is the University of Pennsylvania, offering PennHip testing, the other is the Hip Dysplasia Registry of the Orthopedic Foundation for Animals (OFA) at the University of Missouri.

This article was written in 2006, so thinks may well have progressed since then. I'll do a little more digging, and see what comes up...


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## lauren001 (Jun 30, 2008)

Thanks Dharma66, that is more up to date link than the one I supplied.
*
I quote from the article:*


> New information and research has shown that this disease does indeed exist in the cat and is likely an inherited disorder. No single gene is thought to be responsible for hip dysplasia in either the dog or the cat, but rather a complex interplay of several genetic factors is involved. We do know that if a cat or dog is found to have hip dysplasia, then both its parents must be either affected or carriers of the defect.


I had heard of patellar luxation in some pedigree cats which can also be associated with hip dysplasia and also cow-hocking.

I think the slightly worrying thing is that cats can hide pain very well so some may be suffering in silence, with only those who are in serious trouble showing problems.

BB76 - I think that raising the awareness among breeders of any disease that appears to be an inherited disorder and causes suffering can only be a good thing


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## dharma66 (Oct 25, 2009)

HIP DYSPLASIA: A FELINE POPULATION STUDY by G.G.KELLER DVM,MS, A.L.REED D, VM,MS, J.C.LATTIMER DVM,MS, E.A.CORLEY DVM,PHD, published in Veterinary Radiology & Ultrasound, Vol 40, No. 4, 1999, p p 460-464 gives the following incidences of FHD by breed:

696 cats were studied. The following shows how many of each breed were were found to have FHD over how many of that breed were studied. (for example, of domestics, 35 from 603 werefound to have FHD).

Domestic: 35/603
Abyssinian 0/2
Balinese 0/1
Birman 0/3
Burmese 0/5
Havana 0/1
Himalayan 4/16
Japanese Bobtail 0/1
Manx 0/3
Persian 3/19
Russian Blue 1/2
Siamese 2/28


IMPORTANT NOTE. This is a study of animals that were inspected. Reading those results should not cause alarm. Fro example, you might look at the table and think 'Oh no! Half of Russian Blues have FHD!" The truth is, that is very, very unlikely to be the case. What happened was that two cats of the that breed were examined, and one had it. It may well be that another hundred could be examined, and none of hem have it!

What can be taken from this is that it is definitely not restricted to large cats only. Even a couple of Siamese were found to have the condition.

Another point f interest is tat out of the 81 pedigree cats examined, 12.3% were found to have dysplastic tissue (i.e. to have FHD), whereas 5.8% of domestic cats were affected.

Of the 81 pedigree cats, 40 were male, and 41 female, only 2 males were affected, whereas 8 females were.

This study was of cats presented to the University of Missouri-Columbia Veterinary Medical Teaching Hospital from January 1 1991, through December 31 1995.


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## dharma66 (Oct 25, 2009)

In Veterinary Gross Anatomy: Twelve Smal Animal Clinical Practice Problems, by Alvin F Weber VM, PhD, case of a Siamese is quoted. his cat was diagnosed with FHD, and was relived of lameness by a minor operation. (See Case 5 in this document)


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## dharma66 (Oct 25, 2009)

Prevalence of radiographic signs of degenerative joint disease in a hospital population of cats by
S. P. Clarke, D. Mellor, D. N. Clements, T. Gemmill, M. Farrell, S. Carmichael, D. Bennett from Veterinary Record (2005) 157, 793-799.

This is a study of degenerative joint disease in a hospital population of cats.

Most of the study is concerned wit osteoarthritis, and covers the entire skeletal structure. During the study, it is mentioned that five cases of hip osteoarthritis were found to be caused by FHD. This is from 113 cats, the breed and sex is not specified for those specifically suffering degenerative disease of the hips.

It is interesting that this study and the 'population study' show ~5% and ~6% of cats exhibiting FHD.


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## dharma66 (Oct 25, 2009)

There is only one other article I can find reference to that seems really relevant, and it's not available online.

If anyone has a loft full of back issues of the Journal of the American Animal Hospital Association, I'd be really interested in 1979:5, 447-48, Hayes HM, Wilson GP, Burt JK: Feline Hip Dysplasia.


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## lauren001 (Jun 30, 2008)

Interesting, so perhaps about 1 in 20.
Of course if a popular pedigree stud or dam line were in fact affected or carriers then that would bump up the percentages in any particular breed.


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## dharma66 (Oct 25, 2009)

Indeed. I suspect thats why there's a greater occurrence among pedigrees, due to the reduced gene pool size.


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## BB76 (Sep 9, 2009)

Thank you for all taking the time to read this thread and to share your research - I sincerely hope that the profile of this condition is being raised and every breeder who was not aware of Hip Dysplasia will now ensure they discuss it with their vet before any future breeding is planned. You may also be interested to read about a HD Health Programme which is underway:

PawPeds

Again this highlights the condition, brings awareness that HD is a hereditary defect in cats and more importantly confirms the test that breeding cats should have.

Please do not ignore this test if you are a breeder (especially of BSH cats). Whatever the percentages state I can confirm this is a truly awful condition and not as uncommon as people think and the profile must continue to be raised through all possible avenues. Talk to your vet, add it to your next cat breeding meeting agenda and note on your websites that you test for HD in your breeding line.

Keep posting your research!


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## kozykatz (May 18, 2008)

I would say the numbers of pedigree cats studied are too small to be statistically significant akthough the incidence in Persians/Himalayans (the same breed in effect) seems rather high (and they are a larger breed)

Interesting anyway.

quote=dharma66;1132408]HIP DYSPLASIA: A FELINE POPULATION STUDY by G.G.KELLER DVM,MS, A.L.REED D, VM,MS, J.C.LATTIMER DVM,MS, E.A.CORLEY DVM,PHD, published in Veterinary Radiology & Ultrasound, Vol 40, No. 4, 1999, p p 460-464 gives the following incidences of FHD by breed:

696 cats were studied. The following shows how many of each breed were were found to have FHD over how many of that breed were studied. (for example, of domestics, 35 from 603 werefound to have FHD).

Domestic: 35/603
Abyssinian 0/2
Balinese 0/1
Birman 0/3
Burmese 0/5
Havana 0/1
Himalayan 4/16
Japanese Bobtail 0/1
Manx 0/3
Persian 3/19
Russian Blue 1/2
Siamese 2/28

IMPORTANT NOTE. This is a study of animals that were inspected. Reading those results should not cause alarm. Fro example, you might look at the table and think 'Oh no! Half of Russian Blues have FHD!" The truth is, that is very, very unlikely to be the case. What happened was that two cats of the that breed were examined, and one had it. It may well be that another hundred could be examined, and none of hem have it!

What can be taken from this is that it is definitely not restricted to large cats only. Even a couple of Siamese were found to have the condition.

Another point f interest is tat out of the 81 pedigree cats examined, 12.3% were found to have dysplastic tissue (i.e. to have FHD), whereas 5.8% of domestic cats were affected.

Of the 81 pedigree cats, 40 were male, and 41 female, only 2 males were affected, whereas 8 females were.

This study was of cats presented to the University of Missouri-Columbia Veterinary Medical Teaching Hospital from January 1 1991, through December 31 1995.[/quote]


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## Cerridwen (Jul 26, 2008)

lauren001 said:


> I found this
> 
> Cat Fanciers' Association: Feline Hip Dysplasia
> 
> Study was done in 1998, I am not sure if any further studies have been done.


Worth noting on that study is the low numbers of cats parcipitating. A total of 78 cats and add to that of various breeds. 8 different breeds to be exact. If divided somewhat equal not even 10 cats from each breed. I quote:

_...Dr. Smith was unable to determine whether the hip laxity profiles found in this particular pool of cats is representative of the cat population at large..._

What is interesting is the relationship between PL and HD the researcher found. PL can be diagnosed without x-rays and according to this study it might be adviceable to x-ray the hips of a cat diagnosed with PL.

I don't x-ray my cats for HD but I do have them checked for PL so should I ever have a cat diagnosed with PL I'd probably have it's hips x-rayed.


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## lauren001 (Jun 30, 2008)

Cerridwen said:


> PL can be diagnosed without x-rays and according to this study it might be adviceable to x-ray the hips of a cat diagnosed with PL


Good point.

I also don't think that the numbers affected in any breed are significant in this study, so nothing can drawn from the results other than HD is not a particularly rare condition and if the sample was indeed representative, it is in fact very common.

It is something to be aware of for pet owners and breeders alike and something that perhaps needs to be checked for, if your cat is limping, merely than it being assumed it is trauma or "arthritis" and starting him/her on the meloxicam.


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