Is Dwarfism the same as CD? - Havanese Forum : Havanese Forums
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post #1 of 18 (permalink) Old 08-13-2011, 07:49 AM Thread Starter
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Is Dwarfism the same as CD?

I was wondering if these are the same? Can a dog just be a dwarf, but have straight legs? If so, do they have health issues because of their dwarfism? I read something online that showed dogs that were dwarfed and it made me curious because the havanese was mentioned. It said a lot of the original havanese were dwarfs. The judges were choosing the shorter leg havanese in shows. Well, it said something along those lines. But were their legs actually curved?





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post #2 of 18 (permalink) Old 08-13-2011, 08:38 AM
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Yes, they are the same. I don't think a straight legged dog is considered to be a dwarf. There are short legged breeds, like the Dachshund, some Bulldogs, and Corgi, but their Standards call for short straight legs. Of course, there are still individuals of those that get the bowed legs. Some people say that these are Dwarf, or CD, breeds, but this is not correct. There is no "CD breed".

Chondrodysplasia was a term actually coined by the Malamute folks back in the '70s. Pam was breeding Malamutes for a short time back in the '70s when I met her. I remember one breeder saying that CD legs made them a better pet because they didn't want to run as much, which of course I was horrified by.

The Ostrander study found that all CD, or dwarf, dogs have retrogenes of the FGF4 gene. The Ostrander group was looking for the location to aid in finding out about human dwarfism, and the dog genome made it simple to find. They went to dog shows and took DNA from all the short legged breeds. I don't know that the Ostrander group isolated the gene for short legs. Vetgen is working on a genetic test for it, but it's not done yet.

The Texas A&M study, that self-proclaimed experts say was useless, and others read their own results into it, found that short legged dogs had something like 113 genes that were different on one chromosome, than dogs with equal proportions. The chromosome that the Ostrander group found the FGF4 retrogene, was the same chromosome that TAMU found the 113 different genes on. Equal proportions are legs that were at least as long (in Havanese the same) from the floor to elbow, as from elbow to top of withers. The definition of a short legged dog is one that is shorter from floor to elbow, than elbow to withers. My theory is that short legs are already a retrogene of the FGF4 gene, and CD is a retrogene of the retrogene, by no one has worked on that theory yet.

The Havanese Standard has always called for equal proportions, until someone also added "short legged dog" into the description. This really confused things because when one judge was asked why he picked a particular dog, he said, "because it was the only dog in the ring with short legs". So few people really understand conformation, and leave what is a correct dog up to the Judges.

In any case, it's one of those genetic things with "incomplete penetrance". That a fancy phrase used by geneticists that means even though an individual carries the genes that cause something, they might not exhibit the problem 100% of the time. This is fortunately the case with many other health issues, including the ones that have been found in the 113 genes. It seems that every week another ailment is found to be caused by retrogenes. A retrogene is one that gets put a little bit in the wrong order when an offsprings DNA chain gets out of order in transfer from it's parents.

Last edited by Tom King; 08-13-2011 at 08:53 AM.
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post #3 of 18 (permalink) Old 08-13-2011, 09:19 AM Thread Starter
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Thanks Tom. I am still a bit confused. I know what you are talking about with the proportions. I once saw a diagram and that's what I am referring to. Fred and Bella have the right proportions. Scudder has a very deep chest and it comes to his elbows, where Bella's & Fred's comes to their armpits. The thing is Scudders legs a pin straight! He does have a larger head too. Does this mean he is my little dwarf and will have health issues like a CD dog? He is a cute little dwarf!

Here you can see how deep his chest is. The other pic you can see his straight legs. Not a soaped picture but all I could find right now
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post #4 of 18 (permalink) Old 08-13-2011, 09:42 AM
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I don't think you have anything to worry about. His legs don't look short, and straight is a good thing.

Having the bottom of the chest below the elbow is called "low on leg".

Short legged dogs are usually low on leg, but it can be caused by other conformation too. For example, if the angle between the scapula (shoulder blade) and humerus (upper arm) is less than typical, it will cause the elbow to be a little higher in relation. Also, the upper arm can be shorter than normal. There are endless combinations.
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post #5 of 18 (permalink) Old 08-13-2011, 10:39 AM Thread Starter
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Like that Low on leg sounds better than my baby is a dwarf...LOL. ) I was worried about health issues. Thanks Tom!






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post #6 of 18 (permalink) Old 08-13-2011, 08:51 PM
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Oh your baby does not look like a dwarf!!!!!!! I really do not know about the Havanese but having been in Shih Tzua many long years ago, they do have dwarfism and it has been exploited in the ones they call "Imperial Shih Tzua" there is really no such thing unless you paid $$$$ for one. The dwarf's often have bowed legs, barreled chest and large head, also they have cognitive problems and yes, other genetic problems. OMG I once had a woman tell me her tzu'a big head was a "lion head" !!!!!! You would have already if looking objectively seen dwarfism and your guys all look perfect. I have noticed there is a broad range in the Hav's and some do have shorter legs and I think it might have been a fad at one time, just as Lhasa's today have very long backs, the ones in India and Tibet do not and it is my understanding they are now trying to breed away from it. I love all the pictures you put up of your crew and they are perfect the way they are.

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post #7 of 18 (permalink) Old 08-13-2011, 09:01 PM Thread Starter
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Thanks! I think he is adorable no matter what. Tom explained he is not a dwarf. He is just low on leg!





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post #8 of 18 (permalink) Old 08-14-2011, 04:32 AM
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Scudder looks very handsome in the picture you posted.Our Nellie also has shorter legs [dead straight]and a deep chest,and her head appears to to on the large side,though this might be an optical illusion because her legs are a little short.OMG I'm making her sound like a freak,and she most certainly is not!She is the prettiest little thing.But what I am really trying to say is that there seem to be so many different looks within our Havanese community,you only have to look at all the wonderful photos posted on here.

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post #9 of 18 (permalink) Old 08-14-2011, 06:56 AM Thread Starter
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LOL! You are funny.

I really do think the larger head, deep chest, shorter legs was the preferred look at one time. Scudder also has big bones. I know when he was in the ring, people liked his sturdy look and deep chest. I think Scudders head appears larger because he has huge ears. I swear he could fly! I don't really care how he is put together, as long as he is healthy. Plus, I think he is a very handsome boy!





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post #10 of 18 (permalink) Old 08-14-2011, 10:10 AM
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Linda, I have always thought your Scudder is a handsome boy too - at least, from the photos you have posted. But this is the first time that I have noticed he has one black front leg and one white one! How cute is that?!

Oh Clare, Nellie certainly does not look like a freak!!

Finn has large ears, at least compared to Augie's. I don't remember Augie's looking so large when he was a puppy. Now they are so covered in hair I have no idea. Their ears are so paper thin it is hard to tell where the ear stops and the hair begins.

Linda, Augie & Finn's Mom
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