Eridox - studies - dilution/CDA/BHFD

A study is being conducted by Dr. Tosso Leeb and his team at the University of Berne in Switzerland to locate the dilute mutation in dachshunds and mutation(s) that cause coat disorders in our breed, specifically color dilution alopecia and black hair follicular dysplasia. Researching these mutations in dachshunds will allow geneticists to find the same or similar mutations in other breeds and species, and it is hoped it will lead to genetic tests that can be used by breeders to make more informed breeding decisions.

"D-series dilution" is a pigmentary mutation common to many breeds of domestic dogs as well as other mammals. Black dogs with this form of dilution look grey ("blue") in color, and chocolate dogs a lighter gray ("isabella" or "fawn"). For dogs with this form of dilution who show pheomelanin ("red"/"tan" or "cream") on their coats, the pheomelanin is also diluted, but to a less noticeable extent.

Color dilution alopecia (CDA), also known as color mutant alopecia (CMA), is a common disorder expressed in dilutes. At any time before approximately four years of age, the hair (most often starting on the back and progressing from there) becomes dull, brittle, breaks easily, and doesn't grow back well if at all. Skin hypersensitivity, scaliness, bacterial infections, and related itching may accompany it in some cases.

Black hair follicular dysplasia (BHFD) is a disorder that has much the same appearance as CDA, except that it is expressed in black, non-dilute dachshunds. Those with BHFD begin to lose hair at approximately one month of age continuing until approximately six to nine months of age, and the hair and skin end up the same as a CDA-affected dilute's.

samples needed

Desired for this study are pet owners, breeders, or others who possess:

("related" = "sires and dams with complete litters and possibly siblings or parents, if available")
("unrelated" = "share no great-grandparents")

- unrelated non-dilute/non-dilute-carrying purebred dachshunds over two (2) months of age who have no skin/coat disorders/diseases
- related non-dilute/non-dilute-carrying purebred dachshunds over two (2) months of age who have no skin/coat disorders/diseases

- unrelated dilute purebred dachshunds at least four (4) years old who are unaffected by CDA
- related dilute purebred dachshunds, at least one or more of which is at least four (4) years old and who is unaffected by CDA (some of the relatives of these dogs should ideally be non-dilutes)

- unrelated dilute dachshunds of any age who are affected with CDA
- related dilute dachshunds of any age who are affected with CDA (some of the relatives should ideally be non-dilutes OR dilutes unaffected by CDA)

- unrelated non-dilute purebred dachshunds of any age who are affected with BHFD
- related non-dilute purebred dachshunds of any age who are affected with BHFD (some of the relatives should ideally be unaffected by BHFD)

Needed are as many samples as possible from all the above categories in order to do a thorough genetic investigation of the different issues.

how to participate

Have your veterinarian extract 1-2mls of blood and place in an EDTA (purple-top/anti-coagulation) tube. On each blood sample, clearly label what dog it belongs to. Please include the following information for each dog on a sheet of paper:

· the dog's callname (e.g., "Rover" or "Molly"),

· its breed/variety/type (dachshund, size, hair type),

· its sex,

· its date of birth,

· its color(s)/pattern(s)*,

· a picture of it (can be e-mailed instead; jpeg, jpg, gif, tif, or bmp)

· its 3-generation minimum pedigree (can be e-mailed instead; jpeg, jpg, gif, tif, or bmp)

· what skin/coat condition(s) (disorders and/or diseases) it may have, if any

· a brief description of the texture and luminosity of its coat and if any alopecia is present and where

· if you have any relevant info about its relatives (if sample is singular/unrelated) or its relation to the other dachshunds (if sample is familial/related)

Please also be sure to include the following:

· your name

· your mailing address

· your phone number

· your e-mail address (if you have one)

Anonymity will be given if you request it. (That is, your name, your contact information, and your dog's callname will only be known to those directly involved with the study.)

It is absolutely not necessary, but hair samples from each dog who you have a blood sample for would be very welcome so the researchers can have a good idea of what the coat is physically like. You can collect a few normal, shed hairs (an easy way is to ruffle the fur) from the dog, place them in a small plastic baggie (like a Ziploc baggie), and write the dog's name in permanent pen/marker on the baggie. If submitting hairs from more than one dog, please put each dog's sample of hairs in a different baggie from the others.

Send any electronic files you may have (pictures and/or pedigrees) to

and ship the sample(s) and accompanying information to:

Dr. Tosso Leeb

Institute of Genetics

Bremgartenstr. 109a

3012 Berne, Switzerland

phone +41 31 631-2326

Be sure to pad the sample(s) in bubblewrap or similar material so as to avoid breakage during transit, and be absolutely certain to externally label the package as "diagnostic samples for research purposes; non-infectious, non-hazardous" so it can get through customs without delay. Please use FedEx, UPS, or a similar courier service for shipping, as samples need to arrive in Switzerland within 3-4 days of being taken.

In order to keep shipping costs to a minimum, you can make an arrangement with friends to get your dachshunds' blood taken at once and shipped altogether, or you can contact me and I may be able to help find others near you so you can make arrangements with them.

please note

* Colors and patterns in the dachshund breed can be a bit tricky, as there are so many variations. Please note that the following colors (w/basic patterns) are d-series dilute:

· blue-&-red ("-tan")

· blue-&-cream

· isabella-&-red ("-tan")

· isabella-&-cream

· blue-based red (red with a blue nose)

· blue-based cream (cream with a blue nose)

· isabella-based red (red with an isabella nose)

· isabella-based cream (cream with an isabella nose)

· solid blue

· solid isabella

and the following colors (w/basic patterns) are not d-series dilute:

· black-&-red ("-tan")

· black-&-cream

· chocolate-&-red ("-tan")

· chocolate-&-cream

· black-based red (red with a black nose)

· black-based cream (cream with a black nose)

· chocolate-based red (red with a chocolate nose)

· chooclate-based cream (cream with a chocolate nose)

· solid black

· solid chocolate

It would be very convenient if you could use one of the above terms to describe your dog's color and basic pattern. Please also list any other patterns the dog has (dappling, brindling, wild boar, etc.).

other information

If you would like to submit samples but need financial assistance in order to do so, please contact me.

If your dachshunds cannot participate in the study but you would still like to make a contribution, donations of any amount are very welcome to help cover the costs of taking and shipping blood samples for participants who may need the financial assistance, and if there is any extra left over, for the study itself. Please contact me if you would like to donate.

Thank you very much for your interest in this study! If you have any questions, feel free to contact either Dr. Leeb (

) or myself (

Unless otherwise noted:
All text, images, & audio, unless noted, are copyright by Lisa J. Emerson & may not be used or reproduced without express permission.
All TSL posts are copyright by their respective authors and may not be used or reproduced without their express permission.
All pictures are copyright by their respective authors and may not be used or reproduced without their express permission.