blue/silver born yorkie

[pstinard]

Originally Posted by navillusc

I would be interested in reading whatever you find...but, you probably already guessed that. lol I think it is wonderful that you are here on YT to comment on such things. Thank you.

I was able to find one scholarly article that wasn't hidden behind a pay firewall from my home computer:

http://www.villechamonix.com/userfil...0in%20dogs.pdf

The name of the genetic defect is Color Dilution Alopecia, and it does have deleterious health consequences, mainly baldness and skin problems. That said, we cannot be sure that this is what the OP's Blue Yorkie has--hopefully her Yorkie is blue for other reasons, perhaps a mutation in some other coat color gene that doesn't have these horrible effects. Color Dilution Alopecia is relatively rare, and I pray that this is not what the little one was born with. Definitely take the Blue Yorkie to the vet and ask questions, and keep a close eye on it for signs of premature hair loss. Tomorrow, I will have access to the university computers and be able to access more articles. I'll post more then...

[Prince Toby]

Originally Posted by rekiyamb280

hi to all...
I have two females and one male yorkshires that I breed... been doing it for about 3 years. last night my female had 3 pups. 2 girls and 1 boy. the boy is gray/silver. I IMMEDIATELY started searching the web bc I know the puppies are supposed to be born black. the majority if he's things I read were sooooo negative and demeaning towards the breeder. which I feel is wrong. I found it offensive bc I love my dogs dearly and I take excellent care of them.
it was said that the color is,a recessive gene that can be in either if the parents that gets passed down to the puppy. I absolutely didn't do this on purpose. so I don't know which parent had it. my dam is blue/gold ( she had the traditional silver but her tan has a hue/hint if red- which I call gold) and my sire is blue/tan.
this was sooo unexpected.
some blogs say that the pup will not live past a couple of days, when their color is supposed to change they go totally bald, and have skin issues, blindness... And the bad bad lists goes on. but then I saw some pictures of older blue born pups. they, are not bald, nor blind. but most of them have razor/buz cuts bc the users say their hair doesn't really grow long especially, around the ears.
I also read that there's is two different types of blue borns.
at the end of the day... Im concerned about this little pup and his quality if life. I want to give him a chance.. but then I also don't want to set this pup up food pain and suffering later.
if anyone has a blue/ silver pup or adult dog that can shed some light ot info .. would be helpful.
thanks in advance.
kiya

I have a blue born. She is now 9 months old and doing very good. The only problem she has is growing hair.

[Marhcarter]

I was re reading kendraE's first thread about when Mack was born,http://www.yorkietalk.com/forums/gen...estions-4.html and I was interested in this statement on page 4, 1st post :

Originally Posted by Pinehaven

Luckily, there are labs that can test for this D gene, so if one of the people who purchased a pup from the litter want's to breed, have the dog coat color tested to be sure the results are DD and not Dd (he'd be a carrier if he had a little d in the results). If he's DD, than there is no problem and he's not a carrier ... it's a 40.00 test.

And this:

Originally Posted by Pinehaven

I don't know a whole lot about the blue born yorkie's other than what I've researched and I've known several people who've owned blue yorkies. But here's a link that may help explain the gene involved in the blue born yorkie.

TaylorMadeYorkies.com Blog: BORN SILVER

It says the blue borns have 2 copies of the recessive dilute gene which means that both parents are Dd and the pup got a copy of the recessive "d" from each parent - making the pup dd.

There are tests available for the D/d gene. The company I've used in the past for coat color testing is Animal genetics (Animal Genetics) and you would want to test for the D locus. Good luck.

[gemy]

Originally Posted by pstinard

We are getting close a commercial DNA test to detect genes that are associated with liver shunt problems--that is something that affects several breeds of small dogs, so it's easier and more commercially viable. Traits that affect a single breed, or which don't have as serious a health consequence, will have lower priority and come further down the line--in the case of something as rare as a Blue Yorkie, it could be a few years away, and a more expensive test. I've been doing some searching, and there are all different kinds of answers about the health effects of having a Blue Yorkie. Some say that it only affects hair color. Others say it leads to premature baldness, leathery skin, and premature death. Most breeders never see a Blue Yorkie in their lifetime, so a lot of this information is anecdotal. I hope the OP posts photos and keeps us informed about the health of her blue born as time goes by. And when I get back to work where I have access to our library's computers and scholarly literature, I'll try to find a more definitive answer and post another reply if I do.

Thank you so much. And wonderfull news on the liver shunt. Do you know how the research is progressing on HD and ED?

I really appreciate it, if you can take some of your valuable time, to look up the blue born answer. I might become a bit of a pest

[Prince Toby]

OP, this is my Angel. She has hair everywhere else except closer to her butt area. She has been very healthy, and so sweet.

[pstinard]

Originally Posted by Marhcarter

I was re reading kendraE's first thread about when Mack was born,http://www.yorkietalk.com/forums/gen...estions-4.html and I was interested in this statement on page 4, 1st post :

And this:

There you go . Evidently, there is a genetic test for Color Dilution Alopecia (the "d" mutation). Here is the link to the testing lab:

D Locus

I'll try to find out more information about health problems of Dilute (Blue) Yorkies...

[pstinard]

I was able to find an excellent review article from 2007 that discusses known coat color genes in dogs. Here is the citation:

"Genes affecting coat colour and pattern in domestic dogs: a review," by S. M. Schmutz and T. G. Berryere. 2007. Animal Genetics 38:539-549.

At that time, they had determined that Color Dilution Alopecia was due to a mutation associated with the MPLH (melanophilin) gene. Interestingly, not all dogs that had a mutation in that gene had alopecia (baldness) and other skin problems, so it might be a particular kind of mutation in that gene, or a mutation in a nearby gene on the same chromosome that is responsible for the skin and hair problems. In other words, the good news is that not all Blue Yorkies will necessarily become bald. On the other hand, at the time time this article had been written, they didn't have everything figured out. Here are some brief quotes from that article, then I have to get back to work. I'll try to find some more recent articles later.:

The melanophilin gene

"Many dog breeds have individuals that are grey or dilute in coat colour (Fig. 1i,j). However, blue is used to denote other phenotypes in various breeds. In some breeds, these blue individuals are born grey, whereas in other breeds individuals take several months to turn from black to grey. The latter characteristic was referred to as ‘progressive greying’ by Little (1957) and attributed to the G locus. In some dog breeds this is called ‘silver’. A few dog breeds have both types of grey occurring. Some Great Danes and all Weimaraners are born blue or dilute whereas Kerry Blue Terriers (Fig. 1k) and Old English Sheepdogs are born black and lighten as they grow into adulthood. Both of these inherited traits cause modification of both eumelanin and phaeomelanin pigmented areas to a paler shade, although the phaeomelanin change is not as dramatic as the eumelanin dilution. Fawn dogs with a melanistic mask (Schmutz et al. 2003a) are easier to observe because their mask is grey instead of black. Dilute fawn dogs have charcoal instead of black nose leather and pads (Fig. 1j). Dogs with an e/e genotype at MC1R (Newton et al. 2000) or clear red phenotype, such as the two Beagles in our previous study (Philipp et al. 2005) were very difficult to detect as dilute. Dogs that are brindle and dilute, such as some Whippets and Greyhounds, have grey stripes on a pale fawn background. Dogs, such as Weimaraners, that have two copies of the mutations in TYRP1 causing brown (Schmutz et al. 2002) and two dilute alleles are a pale brown. The nose leather and pads of such dogs are a similar pale brown. In some breeds such as Chinese Shar-Pei, the dogs are called lilac and in Doberman Pinschers, they are called Isabella."

"Recently, we reported that Doberman Pinschers, German Pinschers, Large Munsterlanders, and Beagles with a dilute phenotype, co-segregated with specific haplotypes of melanophilin (MLPH) (Philipp et al. 2005). A mutation in exon 2 of MLPH causes a splice junction problem in homozygous mice of the leaden phenotype (Matesic et al. 2001). The last seven amino acids of exon 2 are spliced out in leaden mice because a C-to-T transition introduces a premature stop codon. A human infant was reported to have Griscelli Syndrome Type III due to a R35W mutation near the end of exon 2 (Ménaschéet al. 2003). The hair colour of this child was not reported but this syndrome is considered a form of albinism."

"We have now extended our study of MLPH to include approximately 20 dog breeds. Although a mutation that co-segregates with blue in some breeds has been found (unpubl. data), no single mutation has been found that explains the blue in all these breeds. A couple of common mutations occur only in blue dogs (unpubl. data). Our study to identify all the alleles causing blue is ongoing."
-------------------
Diseases associated with pigmentation

"Some (n = 30) of the 119 grey/blue dogs we studied (unpubl. data) showed evidence of hair loss and much more rarely skin problems, symptoms typical of colour dilution alopecia (CDA) and black hair follicular dysplasia (Schmutz et al. 1998; von Bomhard et al. 2006). This was not true of all adult blue dogs however. The symptoms also appeared to vary by breed with the Large Munsterlanders displaying complete hair loss in all grey areas by 12 weeks whereas most dogs of other breeds were a few years old before this degree of hair loss occurred. Several dogs 5 years of age or older were reported to have no hair loss or skin problems. Several of the dogs were pups or <2 years of age or had large areas of white fur and therefore we could not determine whether these dogs had or would develop CDA. Dogs that were blue or blue fawn, male or female, long or short-haired and with or without white spots were affected. There may be a slight tendency for earlier symptoms in dogs with longer hair. CDA was reported in 26 of the 100 dilute dogs with a T/T genotype and four of the 19 dogs that showed a dilute phenotype but did not have a T/T genotype at the synonymous c.106C>T polymorphism in exon 2 of the MLPH gene (unpubl. data)."

"Not all ‘blue’ or genotypically d/d dogs (Fig. 1i,j), have problems associated with CDA and not all dogs that have symptoms develop them at a similar age of onset or with similar severity. For example although all Weimaraners are dilute and all of the eight dogs of this breed we studied had a T/T genotype, not all had CDA. Laffort-Dassot et al. (2002) likewise described variable symptoms in five Weimaraners. Miller (1990) suggested that there were possibly multiple recessive alleles of the dilution gene. Although this may be true, it does not appear that dogs with and without CDA necessarily have different mutations in MLPH. Since MLPH binds to RAB27A in the region (Strom et al. 2002) where we have identified some mutations in MLPH, we wanted to determine if a mutation in RAB27A might interact and cause some dogs to experience symptoms of CDA whereas others did not. We sequenced the entire coding region of RAB27A (GenBank DQ494380) in a Large Munsterlander that had severe symptoms of black hair follicular dysplasia, an Italian Greyhound with CDA symptoms, and a black-and-white Large Munsterlander and a chocolate Labrador Retriever which were not dilute and had no symptoms. No polymorphisms in the RAB27A sequence were detected."

[pstinard]

Here is a copy of an email that I sent to Animal Genetics, Incorporated, the company that tests for "D Locus" (color dilution) mutations in dogs. I'll let you know if I hear anything back:

"Dear Sirs,

I am writing to inquire about your DNA testing for the "D Locus" in dogs. I am a geneticist by profession, and I have friends who are Yorkshire Terrier breeders, so they wanted me to ask some questions about the test. One of the breeders just produced a litter with a "Blue Yorkie," and they are concerned about its health prognosis, and also want to eliminate the trait from their breeding stock.

First of all, does your test detect the allele responsible for the production of "Blue Yorkies" that have Color Dilution Alopecia? Can you test the DNA of a Blue Yorkie and determine whether it is homozygous for the mutation causing Color Dilution Alopecia? Do your tests also detect whether a Yorkshire Terrier used as breeding stock is a carrier of the mutation causing Color Dilution Alopecia?

Finally, even if your tests can't reveal anything about Color Dilution Alopecia in Yorkshire Terriers, are they accurate enough to detect carriers for the D locus mutations that are responsible for the coat color of Blue Yorkies? I just want to be sure before recommending that they spend money on genetic testing of their breeding stock.

The reason I'm asking is that I've done literature searches, and the most recent articles that I could access weren't 100% certain whether Color Dilution Alopecia is caused by mutations at the MLPH locus, or whether it is due to other factors that are either linked to the MLPH locus, or which interact with it. If you have citations of recent papers that discuss this issue, I'd appreciate it if you could give them to me. I have access to many journals at the University of Illinois, and I can find, read, and understand any articles that you can point me to. Thanks!

Sincerely,

Phil Stinard"

[pstinard]

Here is one more scholarly article about the association between dilute (blue) coat color and Color Dilution Alopecia: Welle et al. 2009. MLPH Genotype—Melanin Phenotype Correlation in Dilute Dogs. Journal of Heredity 100:S75-S79.

The article concludes that dilute (blue) coat color is necessary, but not sufficient for the development of Color Dilution Alopecia. In other words, not all Blue Yorkies will develop the baldness and skin disorders, but it does dispose them towards developing them. Here are a few quotes from the article:

Coat color dilution in dogs is a specific pigmentation phenotype caused by a defective transport of melanosomes leading to large clumps of pigment. It is inherited as a Mendelian autosomal recessive trait and may be accompanied by hair loss, the so-called color dilution alopecia (CDA), or black hair follicular dysplasia (BHFD). We previously identified the noncoding c.-22G>A transition in the melanophilin gene (MLPH) as a candidate causative mutation for the dilute phenotype. We have now extended our study and genotyped 935 dogs from 20 breeds segregating for dilute coat color. The dilute-associated A allele segregates in many different breeds suggesting an old mutation event. We also investigated skin biopsies of dogs suspected of having either CDA or BHFD, and our data clearly indicate that the dilute mutation is required but not sufficient to develop clinical signs of the disease. The risk to develop CDA/BHFD seems to be breed specific. Interestingly, 22 out of 29 dogs with clinical signs of CDA/BHFD have clumped melanin in the epidermis, the follicular epithelium, and the hair shafts, whereas in dilute dogs without clinical disease, clumped melanin is only found in the follicular epithelium and the hair shafts but not in the epidermis.

-----

Dogs with dilute coat color are known in many breeds. In dilute dogs, the eumelanin- or phaeomelanin-pigmented skin appears paler and is denoted breed specific, foe example, blue, gray, Isabella, fawn, silver, or pale brown (Schmutz and Berryere 2007). As the change in phaeomelanin is not as dramatic as the eumelanin dilution, red-colored dogs are sometimes difficult to detect as dilute. Coat color dilution (d) is inherited as a Mendelian autosomal recessive trait in various dog breeds (Schmutz et al. 1998). Coat color dilution is characterized by a defective transport of melanosomes within follicular melanocytes, which is mainly regulated by 3 interacting proteins (MLPH, MYO5A, and RAB27A) (Barral and Seabra 2004; Hume et al. 2006; Hume et al. 2007). The dilution phenotype occurs in different mammalian species, and causative mutations within the melanophilin gene (MLPH) have been identified in, for example, human, mouse, and cat (Matesic et al. 2001; Ménasché et al. 2003; Ishida et al. 2006). In a previous study, we applied a candidate gene approach and showed that dilute dogs from different breeds share a common approximately 10-kb haplotype block at the 5’ end of the MLPH gene. Within this shared haplotype block, a noncoding single nucleotide polymorphism (SNP) at the splice donor of exon 1 (c.-22G>A) represents a candidate causal mutation for coat color dilution in 7 dog breeds. The MLPH mRNA expression in skin biopsies of dilute beagles carrying the mutant A allele was lower than in beagles carrying the wild-type G allele (Philipp, Hamann, et al. 2005; Philipp, Quignon, et al. 2005; Drögemüller et al. 2007).

Coat color dilution has been described as a predisposing risk factor for certain forms of hair loss in dogs (Mecklenburg 2006). Both, color dilution alopecia (CDA; also known as color mutant alopecia) and black hair follicular dysplasia (BHFD), also known as dark hair follicular dysplasia (Selmanowitz et al. 1972), are primarily noninflammatory forms of hair loss that occur in various dog breeds. CDA is associated with a dilute coat color (Laukner 1998), and hair loss is usually most severe on the dorsal trunk. BHFD occurs in the pigmented coat areas of spotted dogs, for example, in the Large Munsterlander (Schmutz et al. 1998). Some authors consider both diseases to be etiologically identical (Carlotti 1990). BHFD is usually clinically noted within the first weeks of age and comprises fracture of hair shafts in dark coated regions, resulting in partial alopecia and scaling. First clinical signs of CDA are usually noticed between 3 and 12 months of age, rarely later in life, and lesions are usually slowly progressive with age. Affected dogs are prone to secondary pyoderma. With regard to histopathology, CDA is identical to BHFD (Gross et al. 2005, Mecklenburg 2006). Affected skin reveals large clumps of melanin within melanocytes in the hair matrix, the outer root sheath of the hair follicle, and within the hair shaft. The affected hair shafts frequently break within the hair canal resulting in a more or less distorted follicular infundibulum, which is often plugged with keratin, fragmented hairs, and large irregular clumps of melanin. The amount of clumped melanin is variable among breeds and individuals and so is the expressivity of clinical disease (Hargis et al. 1991; Mecklenburg 2006). Some dogs with exactly the same histological findings in the hair follicles have no signs of alopecia, whereas others may have complete hair loss. About 25% of the gray/blue dogs of both sexes show clinical symptoms, whereas the others do not develop alopecia. In addition, not all dogs that have symptoms develop them at a similar age of onset or with similar severity (Schmutz and Berryere 2007). Obviously, some dog breeds, for example, the Large Munsterlander (von Bomhard et al. 2006), develop more easily clinical symptoms than other breeds, such as the Weimaraner, where if symptoms occur at all, they are less pronounced (Laffort-Dassot et al. 2002; Schmutz and Berryere 2007). Unfortunately, no comprehensive study on the breed distribution of CDA or BHFD has been published. A possible influence of other genes besides MLPH influencing the expressivity of clinical disease is under debate, and recently the canine RAB27A gene was analyzed as possible candidate gene. However, no indication for associated nucleotide polymorphisms in the coding region of RAB27A was found (Schmutz and Berryere 2007).

We now conducted an extensive screening experiment to survey in which breeds the MLPH c.-22G>A mutation occurs and for which of the various coat colors in different breeds this mutation might be causative. We also investigated the MLPH genotypes and the histopathological findings in skin biopsies of 45 dogs suspected of having either CDA or BHFD in order to develop an improved phenotypic classification of CDA and a better understanding for additional disease-promoting factors apart from coat color dilution.

---

In conclusion, we found perfect association of the MLPH c.-22G>A SNP with dilute coat color in more than 900 dogs supporting the hypothesis that this polymorphism is indeed the causative mutation. The wide breed distribution of the mutant MLPH c.-22G>A allele suggests an old mutation event. Although our data clearly indicate that the MLPH mutation increases the risk for CDA/BHFD, there seem to be additional modifying factors. A characteristic feature of most CDA/BHFD–affected dogs is the presence of clumped melanin in the epidermis. In some breeds, such as the pinscher breeds and the Rhodesian ridgebacks, the reported coat quality of dilute dogs ranges from normal to severely CDA affected. Therefore, these breeds offer the chance to search for modifier genes, which influence the risk of developing CDA/BHFD in dogs with dilute coat color.

[pstinard]

Originally Posted by Prince Toby

OP, this is my Angel. She has hair everywhere else except closer to her butt area. She has been very healthy, and so sweet.

Angel is a cutie! It looks like she developed only a mild case of Color Dilution Alopecia (just a slight thinning of the hair), thank goodness .

[Nancy1999]

Originally Posted by pstinard

I was able to find one scholarly article that wasn't hidden behind a pay firewall from my home computer:

http://www.villechamonix.com/userfil...0in%20dogs.pdf

The name of the genetic defect is Color Dilution Alopecia, and it does have deleterious health consequences, mainly baldness and skin problems. That said, we cannot be sure that this is what the OP's Blue Yorkie has--hopefully her Yorkie is blue for other reasons, perhaps a mutation in some other coat color gene that doesn't have these horrible effects. Color Dilution Alopecia is relatively rare, and I pray that this is not what the little one was born with. Definitely take the Blue Yorkie to the vet and ask questions, and keep a close eye on it for signs of premature hair loss. Tomorrow, I will have access to the university computers and be able to access more articles. I'll post more then...

Great article, thanks for posting.

[gemy]

[QUOTE=pstinard;4226433]Here is a copy of an email that I sent to Animal Genetics, Incorporated, the company that tests for "D Locus" (color dilution) mutations in dogs. I'll let you know if I hear anything back:

Dear Phil,

On behalf of all YOrkie breeders here, I thank you from depth of my heart, for your willingness to share your knowledge, time, and expertise with us.

What-ever the answers happen to be, they will certainly guide responsible breeders in a much more intelligent fashion.

I also ask permission to forward this information on to the YOrkshire Terrier Club of both Canada and the United States. In part, or in full, as you so wish.

Please private message me your thoughts about this, and we can discuss this further.

Gail E McLarnon Chair of Education Committee - BRTCC Member of the American Working Dog club Foundation. Member of the BRTCA Member and Volunteer in rescue for the Canadian YOrkshire Terrier Association CYTA

Once again my many thanks.

[pstinard]

[quote=gemy;4226496]

Originally Posted by pstinard

Here is a copy of an email that I sent to Animal Genetics, Incorporated, the company that tests for "D Locus" (color dilution) mutations in dogs. I'll let you know if I hear anything back:

Dear Phil,

On behalf of all YOrkie breeders here, I thank you from depth of my heart, for your willingness to share your knowledge, time, and expertise with us.

What-ever the answers happen to be, they will certainly guide responsible breeders in a much more intelligent fashion.

I also ask permission to forward this information on to the YOrkshire Terrier Club of both Canada and the United States. In part, or in full, as you so wish.

Please private message me your thoughts about this, and we can discuss this further.

Gail E McLarnon Chair of Education Committee - BRTCC Member of the American Working Dog club Foundation. Member of the BRTCA Member and Volunteer in rescue for the Canadian YOrkshire Terrier Association CYTA

Once again my many thanks.

Hi Gail, you may use any of the information that I have posted here as you see fit. If you use any of the quoted material from the research articles, please be sure to give the credit to the proper source--I believe that I gave full citations to all of the material I quoted. No need to private message me unless you have further questions or questions that are off the topic of Blue Yorkies .

[gemy]

[quote=pstinard;4226516]

Originally Posted by gemy

Hi Gail, you may use any of the information that I have posted here as you see fit. If you use any of the quoted material from the research articles, please be sure to give the credit to the proper source--I believe that I gave full citations to all of the material I quoted. No need to private message me unless you have further questions or questions that are off the topic of Blue Yorkies .

Thank you very much Phil. I await the response on the email you sent. I will of course make sure all credit is assigned to the proper source.

[pstinard]

[quote=gemy;4226537]

Originally Posted by pstinard

Thank you very much Phil. I await the response on the email you sent. I will of course make sure all credit is assigned to the proper source.

I'm waiting for the response to my email, too. I just want to make sure that they know what they are doing, and that they can DNA test Yorkies for the dilute (blue) coat trait. I'll post their reply as soon as I get it.