# LWO Testing



## CAP (Jun 18, 2014)

I know what LWO is and how it effects horses, but I recently saw on a equine genetic facebook page, that AQHA horses should be tested for LWO before breeding? which with quarter horses I didn't think there was a huge concern there, but I know there is with paints.. 

Now am I correct or were the people on the facebook page right?
What are the odds of a quarter horse carrying LWO and should I be testing for it?.. 

I'm sending papers away to get my one mare's 5 panel test done as I might breed her, I haven't fully decided but when I saw that it made me wonder if I should be testing for that although I didn't think quarter horses were really at risk.

No paint linage in her pedigree and I wont be breeding to a paint horse.


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## DraftyAiresMum (Jun 1, 2011)

Most breeds carry at least one of the white genes that are usually associated with the "overo" coloring in paints. The white on faces and legs has to be caused by some white gene. Frame (also called the lethal white overo gene) is one of these, as is sabino and splash (though splash is to a lesser extent than the other two). 

It's a misconception that the white genes are only found in paint horses. Tobiano is the only white gene that is exclusive to paints/pintos.
_Posted via Mobile Device_


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## PaintHorseMares (Apr 19, 2008)

^^^ This


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## Chiilaa (Aug 12, 2010)

To extend on that - yes, QHs DO have frame within the breed. Lots of them have it.


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## CAP (Jun 18, 2014)

Huh interesting, I never thought of it that way. Thank you


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## verona1016 (Jul 3, 2011)

DraftyAiresMum said:


> It's a misconception that the white genes are only found in paint horses. Tobiano is the only white gene that is exclusive to paints/pintos.


Tobiano isn't exclusive to Paints- it's just not found in AQHA. There are plenty of other breeds that carry it. 

Pinto genes, including tobiano, are of course, exclusive to pintos, since that is the defining characteristic of what it is to be pinto ;-)


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## Chiilaa (Aug 12, 2010)

verona1016 said:


> Tobiano isn't exclusive to Paints- it's just not found in AQHA. There are plenty of other breeds that carry it.
> 
> Pinto genes, including tobiano, are of course, exclusive to pintos, since that is the defining characteristic of what it is to be pinto ;-)


Well.... if you want to be truly correct... pinto genes are exclusive to horses... Because what is considered "pinto" is not actually the full representation of the genes that cause that same thing... Minimal tobiano is the first that comes to mind, but all of them can be rather minimal


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## Horseychick87 (Feb 5, 2014)

Yup, Frame can hide on solid colored horses and that can be dangerous. I may be in the minority on this, but I feel the AQHA, APHA, and even the ApHC should move their 5 panel test up to a 6 panel test with Frame being a required test. You just never know unless you test.


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## Dreamcatcher Arabians (Nov 14, 2010)

Horseychick87 said:


> Yup, Frame can hide on solid colored horses and that can be dangerous. I may be in the minority on this, but I feel the AQHA, APHA, and even the ApHC should move their 5 panel test up to a 6 panel test with Frame being a required test. You just never know unless you test.


I agree with you. I bought a mare who I'd have sworn was frame, was told by her seller she was frame and worried through her whole pregnancy. When I pulled tail hairs to do some testing, I did the LWO test so I'd have written test results and ......... she is NOT LWO. 










This mare is NOT frame. 


















This filly, with similar markings, is frame.


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## Smilie (Oct 4, 2010)

CAP said:


> I know what LWO is and how it effects horses, but I recently saw on a equine genetic facebook page, that AQHA horses should be tested for LWO before breeding? which with quarter horses I didn't think there was a huge concern there, but I know there is with paints..
> 
> Now am I correct or were the people on the facebook page right?
> What are the odds of a quarter horse carrying LWO and should I be testing for it?..
> ...


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## Smilie (Oct 4, 2010)

Here is a case history of a solid AQHA mare that produced an LWO foal. She was bred to a Paint.
While not impossible, it is rare for a solid horse to carry the LWO , thus I would think, breeding a solid AQHA mare to another solid AQHA horse, would not have a risk of producing an LWO

Here is the info and link to that case:

'The lethal OLWS gene is an autosomal dominant with variable expression. Heterozygotes demonstrate assorted white coat patterns, and, on very rare occasions, may be solid-colored; for example, if the dominant lethal gene is not being expressed or has spontaneously mutated. Additional studies are necessary to explain the sporadic occurrence of Overo foals from nonspotted QH parents. Two carriers of the mutated gene must be mated to produce a homozygous lethal white foal. According to Mendelian genetics, an Overo × Overo mating would be expected to produce 25% solid-colored foals, and 50% Overo foals, and 25% OLW foals (1).

Foal with Overo lethal white syndrome born to a registered quarter horse mare


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## DraftyAiresMum (Jun 1, 2011)

Smilie, if you doubt the presence of overo (specifically frame) in non-paint/pinto horses (which is how your posts read), how do you explain white markings like blazes, stars and socks on otherwise solid horses?
_Posted via Mobile Device_


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## SunnyDraco (Dec 8, 2011)

Smilie said:


> Here is a case history of a solid AQHA mare that produced an LWO foal. She was bred to a Paint.
> While not impossible, it is rare for a solid horse to carry the LWO , thus I would think, breeding a solid AQHA mare to another solid AQHA horse, would not have a risk of producing an LWO
> 
> Here is the info and link to that case:
> ...


Even when breeding two solids together there is a risk. You mentioned the solid AQHA mare who produced a lethal white foal. That mare couldn't have had a lethal white foal unless she carries the frame overo gene. You can breed two solid AQHA horses and get a lethal white foal. Most frame overo horses are minimally expressed if expressed at all, crop out AQHA horses are quarter horses who expressed more of the pinto genes than their parents who they inherited them from. The pinto genes quarter horses carry are sabino, splash and frame. These genes typically only express what are known as typical markings like white on the lower legs and feet or white on the face. A horse with only a star or no white at all can still be a carrier of frame. This is why it is so important to test before breeding, that 25% chance of a lethal white happens too frequently and is devasting when it is your own foal that you had invested money, countless sleepless nights on foal watch and hard work into getting on the ground.


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## NdAppy (Apr 8, 2009)

This mare tested positive for frame... The star is her only marking...


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## Smilie (Oct 4, 2010)

DraftyAiresMum said:


> Smilie, if you doubt the presence of overo (specifically frame) in non-paint/pinto horses (which is how your posts read), how do you explain white markings like blazes, stars and socks on otherwise solid horses?
> _Posted via Mobile Device_


No, that is not what I implied.
According to that article, it is rare for a horse that carries the LWO, not to have an expressed coat pattern
Not all overos carry LWO, as we all know the statistics when breeding two overos together that do carry LWO, to produce that homozygous and affected offspring is 25%
Having stood an Appaloosa stallion that was double Mighty Bright bred, I am more that aware of the overo gene being carried by many breeds, often with expression limited to blaze, socks.
What the article implied though,as I( read it, is that it is very rare for a solid horse that is carrying not just an overo gene, but an LWO, not to have color expression, beyond socks and blaze


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## Smilie (Oct 4, 2010)

NdAppy said:


> This mare tested positive for frame... The star is her only marking...


 But, the question is, did she test positive for LWO? Not all frames carry LWO


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## NdAppy (Apr 8, 2009)

Frame _*IS*_ LWO there is no separating frame overo from LWO. If you're horse is frame it's a LWO carrier.


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## Dreamcatcher Arabians (Nov 14, 2010)

Smilie said:


> But, the question is, did she test positive for LWO? Not all frames carry LWO


Splash, sabino are different Overo patterns, but there's only one frame and it is LWO.


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## Smilie (Oct 4, 2010)

I have not researched into LWO that extensively, thus really do not know of the data that exists, far as a frame overo, solid colored, can carry LWO, and was merely reading that article, which implied that it was rare
That in no way meant that I discounted frame overo genetics being carried by many breeds, and I certainly know some Appaloosa lines carry it, esp those of Mighty Bright, who was sired by Bright Eyes Brother , rumored to be a full brother to the AQHA champion running mare , Maddon's Bright Eyes. Look at their common dam, Plaudette, and she very obviously has paint genetics
I never had an LWO foal, but I did have one that could not get ApHC papers , due to the size of a belly spot

This is the picture of that stud, and just looking at my horse Smilie, a daughter of his, out of an AQHA mare, it is very obvious that she carries some overo genetics










Thus, I am not arguing the point that many breeds carry the overo gene, with expression limited to facial and leg markings. I don't even know as to whether LWO is rare, carried by a solid colored horse, as opposed just to a copy of frame overo. I was merely reading what I thought that article stated.
I would also be interested in some statistics, as I am completely in the blind,far as LWO being carried by solid horses, versus just frame overo


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## Smilie (Oct 4, 2010)

Dreamcatcher Arabians said:


> Splash, sabino are different Overo patterns, but there's only one frame and it is LWO.



Ok, that is something I did not know, that any horse that carries frame overo also then carries LWO, and there are no frame overos that don't have LWO genetics


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## Poseidon (Oct 1, 2010)

Smilie that is exactly what they're trying to say. Overo is a blanket term for anything that isn't tobiano. It is misleading and annoying for the rest of us.


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## Smilie (Oct 4, 2010)

This is the info that I have found thus far

think we may find out that there are genetic differences between splashed whites, sabinos and frames, just like there is more than one gene that controls spotting in mice. With this, it is possible that not all combinations will produce a lethal  white foal in the homozygous state. How that all sorts out is going to be very interesting. It would seem that frame horses tend to be the ones that are most likely to produce a lethal white. But we have seen lethal whites out of sabino stallions. And splashed whites are so uncommon that I'm not really sure how they fit in. We are going to try and stick with the frames in our study for now, because that will make it simple. But then we'll branch out into the other types of overo.​ Something else that I think is a bit of a problem is, what is an overo? Dr. Phillip Sponenburg says that overo has come to mean anything that is not tobiano. 



So, is there now an actual genetic test to differentiate a frame overo from just an overo?


Okay, learn something new! Wonders of google! I do see that there indeed now is available a genetic test for frame overo!

This documentation is important for breeders of Paint Horses. With DNA tests now available for the frame gene (and the lethal white foals that can accompany it) it is possible to test breeding horses. Those with the gene can be mated to horses without it, resulting in about half frame and half nonspotted foals, but avoiding completely the production of lethal white foals. 
​


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## Poseidon (Oct 1, 2010)

If you'd like another example of a frame/LWO horse that is solid in appearance, here:










A buckskin frame. Her dam is very loudly colored, so I tested my mare as well. She's frame. 

These are her test results from 3 years ago. She was also tested for splash, which is clearly negative. But note that "Frame Overo" is not an option, but is instead listed as Lethal White Overo. Because they are the same thing.


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## NdAppy (Apr 8, 2009)

Smilie... Please link where you are getting your information. 

There has been a test for years for LWO and Animal genetics out right states that Frame overo = LWO.


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## Poseidon (Oct 1, 2010)

Smilie, what year was that information published? Because the last 5 years has made HUGE advances in the differentiating of the different white pattern genes. Hell, we have over 20 White Spotting patterns (formerly known as Dominant White) that appear to just keep mutating.

Edit: To add to that, the Splashed White tests were developed literally only a couple of months before I did my testing. The date is at the top and was just over 3 years ago.


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## Smilie (Oct 4, 2010)

Poseidon said:


> Smilie, what year was that information published? Because the last 5 years has made HUGE advances in the differentiating of the different white pattern genes. Hell, we have over 20 White Spotting patterns (formerly known as Dominant White) that appear to just keep mutating.
> 
> Edit: To add to that, the Splashed White tests were developed literally only a couple of months before I did my testing. The date is at the top and was just over 3 years ago.


Yes, if you go back to my last post, you will see that I did find out by googling some more, that a test now exists for frame overo, and that frame overo always carries one copy of LWO.
Never too old to learn something new!
I admit, having raised Appaloosas for many years, I was not really that Familiar with Paint genetics,( I know, only Tobiano is truly a Paint exclusive genetic color gene) but overo is none the less a Paint coat color , even though many horses carry it At one time, those white markings on face and legs on other breeds, were accredited to the sabino gene
White TBs, for instance, were considered ultimate expression of the sabino gene
Genetics is an on going field of knowledge.
As an Appaloosa breeder, I have been more concerned with CSNB, linked to the LP complex, and the color production of a true few spot

I find the frame overo facts interesting, esp since AQHA is an allowable outcross for Appaloosas, and many Appaloosa performance breeders have used that out cross extensively Then of course, as we all know, many of those genetics were included into all three of those stock horse registries, as those registries were first formed by selecting visible coat patterns

Many roan and solid Appaloosas were put into the AQHA registry and explain those loud colored foundation Appaloosas that resulted from two AQHA parents. Wapiti, Bright Eyes Brother , are just two examples

In fact, there is at the moment a loud blanket marked Appaloosa colored stallion that is registered also AQHA, due to the relaxing of the white rule, and whose parents are both registered AQHA

What I'm saying, is that those genetics, are there, even if they have not been expressed for several generations, and thus I am surprised that I never heard of an Appaloosa foal born with LWO. Just luck?
Someone know of a case? 
I admit that I always thought that LWO was just a Paint horse Breeder's concern
So then, since many breeds have Arabian blood, plus ApHC allows for that outcross,should all horses then also be tested for CID ?


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## NdAppy (Apr 8, 2009)

Luck and the fact that most ApHC breeders are not going to talk about it or admit it while putting the loss of the foal down to foaling complications or something similar. 

Remenic in Spots is brought up quite often on this forum when the discussion of AQHA white rules is brought up. 

There are also frame overo JC registered TBs as well. Frame is also in miniatures as well as a few other breeds.


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## PaintHorseMares (Apr 19, 2008)

NdAppy said:


> Luck and the fact that most ApHC breeders are not going to talk about it or admit it while putting the loss of the foal down to foaling complications or something similar.


I imagine this is why there are no good stats about LW out of solids, too.
_Posted via Mobile Device_


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## Dreamcatcher Arabians (Nov 14, 2010)

Purebred thoroughbred by Racey Remarque X Dance Spot. Dance Spot was by my stallion Dancebel. 










Dance Spot by Dancebel X Stun (The Irish Lord) All of Stun's relations appear to be solid, though some have high socks and facial white. 










Dancebel. Dancer didn't look like he could throw such crazy color, but he did, over and over and over.


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## Smilie (Oct 4, 2010)

Okay, but that still does not answer the question, that if you breed an ApHC or AQHA horse to a solid AQHA horse, how likely is it that both would carry the frame overo, and without any expression, and thus produce a LWO foal? I think that would be rare
I can see testing your AQHA horse, if breeding out to an APHA horse, or your App horse , breeding out to an AQHA horse that is dual registered
I think, far as recessive genetic defects, that affect stock horses, other that Paints, GEBD and HERDA are much more likely
On the other hand, what is one more genetic test, but those tests could,be endless, where any cross breeding occurs
I mentioned CID, so any lines that go back to an Arabian, should be tested, if you follow that line of thinking
What about a true roan gene? It is though that the homozygous state is lethal.
So, is this info now not correct?

More Info • Although a horse may have the frame pattern, he may not carry the OLWS gene • Not all white foals born are OLWS foals, some just have a white coat • Many carrier horse areA horse with the frame pattern. He is a bred either intentionallycarrier of the lethal white gene. or accidentally because the frame coat is a very popular coat back to table of contents 

Here is the link It is from 2012, so could be out of date

Equine genetic disorders

JEB is found in Belguim horses, so should all those that breed out to drafts, in the Sport horse industry, be testing for JEB?
What about lavender foal syndrome, found in Egyptian Arabians?

I guess , what I am saying, is even now, were I still actively breeding Appaloosas, and crossing out to a solid AQHA horse, I doubt whether I would feel the need to test for LWO.
However, I have no argument with those that feel it should be done


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## Dreamcatcher Arabians (Nov 14, 2010)

Since it's a $25 test, and the alternative is possibly a foal dying in agony because you didn't, I'd go ahead and do it. Just to be safe. 

I feel VERY strongly about it, since I used to routinely breed my "solid" stallion to other "solid" mares and get crop out foals, before we knew a lot about LWO and there was no test. Now? There's no excuse for another foal to die because "I didn't know.".


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## nikelodeon79 (Mar 3, 2008)

Dreamcatcher Arabians said:


> Since it's a $25 test, and the alternative is possibly a foal dying in agony because you didn't, I'd go ahead and do it. Just to be safe.
> 
> I feel VERY strongly about it, since I used to routinely breed my "solid" stallion to other "solid" mares and get crop out foals, before we knew a lot about LWO and there was no test. Now? There's no excuse for another foal to die because "I didn't know.".


THIS.

I cannot understand why you wouldn't test even if the chances are low. The chances could be ZERO.
_Posted via Mobile Device_


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## SunnyDraco (Dec 8, 2011)

Smilie said:


> Okay, but that still does not answer the question, that if you breed an ApHC or AQHA horse to a solid AQHA horse, how likely is it that both would carry the frame overo, and without any expression, and thus produce a LWO foal? I think that would be rare
> I can see testing your AQHA horse, if breeding out to an APHA horse, or your App horse , breeding out to an AQHA horse that is dual registered
> I think, far as recessive genetic defects, that affect stock horses, other that Paints, GEBD and HERDA are much more likely
> On the other hand, what is one more genetic test, but those tests could,be endless, where any cross breeding occurs
> ...


The internet is full of information and anyone can post anything they so desire and seem correct. Could be outdated information or personal thoughts written to look like facts. I personally prefer reading information published directly from the researchers who are identifying the differences in DNA. There are continual studies and research about horse genetics and great advances in knowledge that expand our understanding. 

Since you brought up roans being thought as lethal in homozygous, there are homozygous roans out there who have tested as being homozygous. Roan

And as far as lethal white, read this: Lethal White Overo - Horse Coat Color

If there is testing for genetic diseases for those known diseases to a horse's breed, yes you should test. There are so many gambles that are made as it is when you breed, no point in adding known and testable genetic diseases to the list of what can go wrong. As far as frame colored horses not carrying lethal white, it is more likely that there is an imitation of frame (like some purebred Arabians look like they carry tobiano which is not in the breed and test negative for it) or the mutation occurred in a different location from where UC Davis or another testing lab checks (read last paragraph on the page about lethal white). It is also believed that some splash mutations are lethal in homozygous form but it is hard to prove if they die inutero and are easily passed off as the foal being slipped. When we have a foal born alive, full term and there is a life ending or health problem, researchers can study and try to investigate if it was environmental or genetic. From there they can continue research about the causes and sometimes identify the exact problem which can prevent other effected foals if breeders avoid certain breedings (genetic) or exposures (environmental). My mom had a mustard foal (environmental problem) and was lucky it was a mild case which allowed the foal to survive with minimal treatment (it is lethal to foals of more severe cases) and then she took steps to avoid a repeat which has prevented having another effected foal. 

While you may not feel the need to test if you were still breeding Appaloosas, I bet that mindset would change the moment you had a lethal white foal and had to make the choice between humane euthanasia or watching the beautiful foal slowly die in agony for approximately 72 hours. You don't even need to outcross to solid AQHA either, it can already be within the breed as ApHC has allowed outcrossing with jockey club and AQHA for many years. ApHC already has to deal with HYPP and other AQHA genetic diseases. Lethal White is famously known in APHA horses as there are many breeders who breed for loud frame expression which created a large number of lethal white foals as the 1 and 4 chance was frequent. It is not exclusive to APHA horse or horses with pinto patterns, it has been found in several breeds and is always lethal and awful odds when breeders cross two carriers. It doesn't even increase your odds of a foal getting frame passed to them if breeding two frame carriers, it only divides the chance of a healthy non frame foal in half with a chance of a foal to be euthanized or watch die in agony. 

Basically, it is not worth the risk. For $25, you can know if you have a risk of lethal white in which case you are VERY selective to choose a tested non carrier or if you shouldn't need to worry about lethal white. But keep in mind, UC Davis has a warning that it is possible for NN horses to produce a lethal white if the mutation was not where they test for it.


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## Chiilaa (Aug 12, 2010)

There have been lots of ApHC horses testing positive for frame. I think the reason there are not more is because of that distinction people want to make - "my horse is not paint, I don't need to worry about it being LWO".

Additionally, frame on its OWN is quite normal as far as we can see. In fact, in breeds where white is actively discouraged, such as the AQHA (I know they have since relaxed the white rule) and the ApHC (pinto patterns here) it is far more common to see just one or two of the white patterns, rather than a horse that carries four of them and is loud. Frame without any other white pattern is thought to actually be rather minimal in its expression, rather than the loud "overo" pattern we are used to thinking of when we hear it.

This is an ApHC registered mare that is frame positive:










Short But Sassy Appaloosa


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## FrostedLilly (Nov 4, 2012)

LWO/frame overo is present in many breeds. Off the top of my head, along with the breeds mentioned above, it's present in Miniatures, TWH, Saddlebreds, and a select few Morgans. As other have said it's such a cheap test there's no reason not to test.


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## nikelodeon79 (Mar 3, 2008)

The breeder I got my American Shetlands from said there is frame in Shetlands now, as well.
_Posted via Mobile Device_


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## Chiilaa (Aug 12, 2010)

nikelodeon79 said:


> The breeder I got my American Shetlands from said there is frame in Shetlands now, as well.
> _Posted via Mobile Device_


It is important to clarify that it is in AMERICAN Shetlands, not in "classic" Shetlands.

Other breeds it is in are:

American Paint Horse
American Quarter Horse
American Indian Horse
American Shetland Pony
Miniature Horse
Mustang
Nokota
Spanish Mustang
Spotted Kentucky Mountain Saddle Horse
Spotted Saddle horse
Tennessee Walking Horse
Thoroughbred

Breeds that MAY have it based on phenotype, but have not (as far as I am aware) tested positive YET:

American Saddlebred
American Warmblood
Australian Draught Horse
Australian Stock Horse
Azteca
Campolina
Criollo
Curly
Falabella
Gelderland
Missouri Fox Trotter
Morgan
National Show Horse
Quarter pony


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