Border Collie with Colour dilution alopoecia
Photo Credit: At the VETS Veterinary Clinic
What is color-dilution alopecia?
Color-dilution alopecia is a hereditary skin disease found in “color-diluted” dogs caused by the d1 allele of the color dilution gene (Kim et al, 2005). The Miniature Pinscher is one dog breed affected by this disease. Color-diluted Min Pins are either “blue,” which is a diluted black, or “fawn,” which is diluted chocolate. The color dilution phenotype is carried by an autosomal recessive gene. Thus, the dogs can be carriers of the gene without having a diluted color itself.
Color-dilution alopecia is also known as the following: blue balding syndrome, blue doberman syndrome, congenital alopecia, and blue dog disease. (Kim, et al, 2005).
Color-diution alopecia causes patches of hair loss and scaly skin mainly on the trunk and back. Although it develops at a young age, color-dilution alopecia is not present at birth.
What is an allele?
An allele is a gene variant. Take blood type, for example: A and B are different alleles of the same gene. They have the same function, but the DNA sequence is slightly different. Often, two alleles can differ by as little as one letter (base) in a DNA sequence. This is amazing given the fact that it is only one change in possibly millions.
What does “autosomal recessive” mean?
Autosomal simply means that the gene is not on one of the sex chromosomes (X or Y). Recessive means that the trait will only appear if two of the recessive alleles are present (dominant alleles are not present).
What are colors are recognized by AKC?
Standard: Black & Rust, Black & Tan, Chocolate & Rust, Chocolate & Tan, Red, Stag Red.
Alternate: Blue & Rust, Blue & Tan, Blue Stag Red, Chocolate Stag Red, Fawn & Rust, Fawn (Isabella) & Tan, Fawn (Isabella) Stag Red.
Dogs with standard coat colors are allowed in conformation, obedience, and agility whereas alternate colors are only allowed in obedience and agility.
I have owned blue and/or fawn Min Pins before and they have been perfectly healthy. Why should I worry about breeding them?
The d1 allele of the dilution gene (d17) is likely responsible for color-dilution alopecia (Kim et al, 2005). Since there may be more than one allele that can cause color-dilution, it is possible that any one particular genetic lineage may not be at risk for the disease. However, until more is known about the disease, there is not way to tell which dogs with dilute coat colors are carriers of the d1 allele. Thus, breeding dogs with dilute color or a dilute color in the lineage is not congruent with breeding for the betterment of the breed.
I want to buy a blue or fawn Miniature Pinscher. How can I avoid buying a puppy with color-dilution alopecia?
The short answer is: “You can’t.” Color-dilution alopecia is not present at birth and may not manifest itself until the pup is as old as 2-3 years (Derm Digest, 2010). If you know there is not any color-dilution alopecia in the pup’s lineage, you might be able to more likely to avoid the disease, but I suspect that breeders either don’t keep or may not want to share that information. Thus, it would be difficult to adopt, with any degree of certainty, a healthy blue or fawn puppy with a dilute coat color.
I have a color-diluted Min Pin. Is there anything I can do to prevent color-dilution alopecia?
Since color-diluted alopecia is a genetic disorder, there is no cure. However, you can watch for red, scabby bumps with a “bloody” appearance. This is a sign of a bacterial infection, which commonly develops in the patches affected by color-dilution alopecia..
For further information
Jae Hoon Kim, Kyung Il Kang, Hyun Joo Sohn, Gye Hyeong Woo, Young Hwa Jean, Eui Kyung Hwang. (2005). Color-dilution alopecia in dogs. J Vet Sci. 6(3): 259~261.
Color Dilution Alopecia. Aug. 2010 Newsletter. Derm Digest. Animal Dermatology Clinic.
Hereditary Alopecia and Hypotrichosis in the Merck Veterinary Manuel.
Colors and Markings (Miniature Pinscher) on the AKC web site.
