merle chihuahuas: potential health problems from the merle color gene

famous chihuahua editor chihuahua facts, chihuahua health concerns 20 Comments

merle chihuahua

what exactly are merle chihuahuas?

merle chihuahuas are said to be the latest ‘style’ or ‘designer color’ to gain popularity within chihuahua breeding during the past 15 years, but due to potential health problems, merle chihuahuas are rarely mentioned in credible books about genetic coloring patterns of the breed.  chocolate and long haired merle chihuahuas are also a rare find, thus making them more desirable to people who are more concerned about making a ‘fashion’ statement.

how does merle breeding work?

the merle gene will change the pigmentation of their base color causing them to have a lighter colored spots throughout their fur coat.  merles can create very intriguing and unique colored chihuahuas and at times will often have blue eyes.  the merle gene is also a dominant gene. this means that one parent must be a merle for the gene to be passed on to their offspring.  thus the gene will not remain dormant for many years and then suddenly surface.

merle chihuahua puppy

are merle chihuahuas show worthy?

at one time, merle chihuahuas were eligible for show and were even considered to be purebred by AKC, CKC and KC standards.  however the rules changed as merle chihuahuas grew less likely to be purebreds and more breeders were just creating mixed breeds with false registration papers.  merle chihuahuas were also suspiciously increasing in size getting as large as 10 lbs!

are merle chihuahuas more prone to health problems than other chihuahuas?

the most controversial and debatable issue with merle chihuahuas is if there exists an increase in potential health problems.  if a breeder does not breed responsibly, then there definitely exists an increased health risk with merle chihuahuas, but if a breeder breeds responsibly and is credible, merle chihuahuas are typically happy and healthy just like all other chihuahuas.

a breeder does not breed responsibly if they mate two purebred merles together, where both parents are merles.  by doing so they think they are strengthening the merle color, but in actual fact they are creating a recipe for disaster as the double merle gene can create chihuahuas with serious health defects that include blindness, deafness and even severe deformities.

are there any other health problems in merle chihuahuas?

sometimes merle chihuahuas are sensitive to sunlight when they have the blue eye color, so it’s important to keep this in mind when outdoors on those bright and sunny days.

so what does all this mean?

merle chihuahuas are just as lovable as other chihuahuas.  it is irresponsible breeding practices that lead to major health problems in merle chihuahuas.  so do your research and ask questions if you are considering getting a merle chihuahua.  don’t be afraid to investigate the breeder.  we’d also recommend that you consider rescuing or adopting a chihuahua from a shelter because those are the chihuahuas that need you the most!




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Comments 20

  1. julian. O'Donnell

    I own a small merle bitch with short but dense coat, she is unbelievably athletic and runs with my large lurcher and saluki covering at least 6 miles 5 days per week, she is always the 1st one of the couch once the leaders are picked up and forever in the thick of it.
    Don’t be put of having a merle, a well bred dog is a fit dog.

  2. Teri (Grammar Dragon)

    I rescued what appears to be a blue merle long hair chihuahua. He had been a stray but was judged to be less than a year old, so possibly an abandoned puppy. He is estimated to be nearing a year old so we’ve decided his birthday will be 4/1 – April fool’s day.

    He is deaf and has a tiny eye and an off center pupil in the other eye. The shelter vet suggested he was blind or partially so. So in other words he was an undesirable. However he loves his home with us and judging by the way he races around the house and furniture, I don’t think blindness is currently an issue. People ask his name and for some unknown reason the shelter named him Echo. He can’t hear anyone so his name makes no difference to him. We’ve developed a form of sign language that he responds to. And we are currently working on ways for him to better signal his needs to us.

    One benefit of his deafness is he doesn’t bark except to “talk” to us. He is so friendly with people including babies, toddlers, and kids in general. I can take him anywhere and since we are RVers we plan on doing so. He stays close to one of us all the time and is currently asleep on my lap as I write this.

    I feel like he was the result of irresponsible breeding and I know that he may not have a long life but I feel like I found him because he needed us and I hope to make his life a happy one!

  3. Skye

    Cheryl Pitts
    If you are certain of the lineage, then there are 2 possibilities as to where the Merle came from.

    1)This one is the least likely. There is a slim possibility that your Chihuahua could be a Cryptic Merle. This occurs when the Merle gene is shortened when it is passed onto the puppy from it’s Merle parent. Cryptic Merle dog’s have very little Merle in their coat, normally a small amount around the face, although this could be mistaken for greying from age and around he tail and any white edges, however, if the dog in question has a lot of white then the small amount of Merle it would have had could be masked by the white. If the Cryptic Merle were to have puppies then the Merle gene could lengthen and produce normal Merle offspring. However, considering your description, due to the small amount of white on your otherwise black dog, this possibility is unlikely.

    2) The most likely possibility is that the father, whom you said is completely tan, is a Hidden Merle. What this article fails to explain, is the nature of the Merle gene. Merle is a pattern dilution gene. This means that the dogs original coat colour is diluted by the Merle gene in a pattern unique to every dog. For example, Blue Merle is the result of the Merle gene over a black coat while Red Merle is the result of the Merle gene over a chocolate coat. The Merle gene is not physically displayed in coat colours that are too pale for the Merle gene to dilute, this includes; red/tan, gold, cream, sable and fawn. If a dog is any of these colours and carries the Merle gene, then it is a Hidden Merle. Considering the father is red/tan, chances are good that he carries the Merle gene but does not express it himself due to being an incompatible colour.
    The only way to know for certain is to get one or both dogs tested for the Merle gene. I hope this helped.

  4. Cheryl Pitts

    I have a pure bredApple head Chihuahua her name is Angel, I adopted less then a year ago back in March2016, I didn’t know at the time when I adopted her that she was pregnant, she got bred by a purebred miniature dachshund so Angel had 3 male ChiWheeny Puppies all are just adorable puppies and all have been adopted I adopted them out to people who NEED THEM, medically speaking and as untrained service dogs for the folks I gave them to.
    Each puppy was different colors,
    2 puppies Took After Each Parent and 1 is a Merles Colored,
    My Angel Is a All Black with white marks on her chest and feet, she had a puppie Colored Just Like His Momma.
    The Father”Miniature Dachshund ” is ALL Tan Colored, and Angle had a puppy Colored Just Like His Papa, I don’t know where the Merle Colored Come From ? I know Dachshunds have that Merle Colored in them also, but would it be more likely that my dog past that gene on to her puppies ? Or could they both of past on that gene? and will they all have health issues if they all have that gene, the puppies won’t be passing on the gene As They Are All Neutered by now and my Angel has an appointment to get spayed in Nov. she is 5 years old and this litter of puppies is her first and only litter of puppies, as it has aged her, but boy she was a Class “A” Momma, very clean about the whole idea of puppies and very protective of those puppies to .

  5. Caro

    Lily Allen,
    I think you are confusing a “standard Chihuahua” with a “healthy dog”. A well balanced Chihuahua’s STANDARD weight should NOT exceed 6 pounds. “Purebred” was in the question because if you go back and trace the Merle Chihuahua’s line you may find something that is not purebred OR irresponsible breeders breeding MERLE Chihuahuas that DO NOT fit the standards of the breed just for color (therefor bringing EVEN MORE Chihuahuas into the world that do fit the breed standard), thus the HUGE Chihuahuas we see around today weighing WELL over 6 pounds. Purebred meaning all ancestors derive from, over many generations, the same recognized, standerdized breed. Just wanted to you to be more informed, that’s all. =) I own a red and chocolate 4 pounder female and a chocolate merle 4 pounder male ♥ #chihuahualover

  6. Lily Allen

    I have to disagree with one part of this.. the sizing comment. I just adopted a blue merle girl today and she is a bit overweight. She is about 13lbs. She is also a standard size chihuahua and those are normally 8-10lbs. So to make a statement that a merle is not pure bred because they can reach a whopping 13lbs, should not make statements without having facts.

    This is my second long hair standard sized chihuahua. Gizmo was my first and he was chocolate and tan. He was purebred and weighed, you guessed it, 10lbs. There is nothing unusual about a chihuahua at that weight. Tea cup chihuahuas are not normal but most people think that’s how small they should be and it isn’t.

    I looked into all the health issues and hopefully my new girl stays healthy once I bring her back to NORMAL 10lbs for the standard size chihuahua that she is.

  7. Danna

    AKC allows Merle patterned Chihuahuas to be registered and shown. There are countless, merle patterned Chihuahua’s, with their championships and DNA to prove they are indeed pure bred Chihuahua’s.

  8. Barbara Brown

    I have a long coat chocolate merle female that is currently bred to my fawn & white long coat male. Breeding merle to merle is an absolute “no no” to anyone that is breeding. It is long proven that merle to merle breeding is disastrous in so many ways. The breeders who actually care about the dogs they are rearing would never consider doing this due to the dangers to offspring. I am proud to own such a rare coloring in one of my dogs, but I have done in depth studies on breeding of the merle pattern. Anyone wishing to raise the these amazing pets should do so armed with knowledge… just as they should arm themselves with knowledge regarding any breed, species of animal. No one should be breeding animals simply for the money they can stand to make off the sale of offspring.

  9. Denise Laney

    Wow I just purchased a chocolate one and I must say that I did not do my homework I’ve learned so much just reading this and pray that I don’t have any problems, I don’t know what to think anymore I thought it was just a name had no idea about the health problems that came with this name I would have just purchased a regular long coat in which I thought I was doing

  10. Ulla Duchwaider

    I have a brown Merle Chihuahua, and one of his pops. The pop is black & tan, with a white mark on the breast, after his mother. The father is named Merling, hi hi

    Lulu of Denmark Dog psykologi .

    As Cesar Millan’ way.

  11. Nancy Arends

    My little boy, a Blue Merle, had a heart murmur. I actually found a cardiologist for him, and despite our efforts, we had to say goodbye to him last October because he was in congestive heart failure. He was six. I did not acquire him because he was a designer colour. I just loved him because he had the sweetest disposition. I miss him every day. I hope heart defects are not common because it is a horrible experience for these dogs when their breathing get more laboured and they are dependent on medicine to get through the day.

  12. pamela gardner

    There is a blue merle precious Chi at Rocky Mt. Animal Shelter currently. If not rescued she will be killed on Thursday morning. Can anyone help?

  13. Melba Wiley

    The point of not breeding a Merle to a Merle in any breed is correct. I have a long coat blue Merle male & a long coat chocolate Merle female Chihuahua. No relation & NO WAY WOULD I EVER BREED THEM TO ONE ANOTHER. I did a lot of research on the gene when I got my first one. I am advertising my first litter of Merle Chihuahua puppies now & I am putting on each puppies ad that they can not be bred to another Merle patterned Chihuahua.

  14. Michelle DeFaut

    Any of the standard colors can be weakened by poor breeding. Times have changed and you can’t put those horses back in the barn. Banning colors or markings after accepting them is terribly unfair. Breeding education would be the answer.

  15. Kathy Sherwood

    My girl is aprox 15 months and has beautiful markings. She is cream/tricolor with merle patterning and a brown eye and blue eye. She is so precious. So much fun and full of energy. I got her at a shelter who said they found her not far from where I live.

  16. Carol M

    My chi has a merle mother. mine is chocolate and tan and has larger ears than most. he is long-haired. his undercoat is tan with almost a bluish tingsh. I got him shaved down one summer and discovered this. I thought it was a different dog when I picked him up. seriously. the only problem is his back legs which seem to come out of joint when he sits and relaxes. is this part of the health problem with the merle gene?

  17. Wendy Ryan

    Merles of ANY breed can have health issues if irresponsibly bred. Collies, Aussies and any other breed with the merle pattern can have issues if 2 merles are bred. I don’t think we should condemn chihuahuas in particular. I also think this link was misleading in that it looked like it would show an unbiased view of merle patterned chihuahuas and to me it was inaccurate and biased…

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