Color Mutations in Dobermans

Dilution Alopecia and Partial Albinism

History

Dilution Alopecia
  • Genetically inherited disease
  • Dobermans are the most common breed affected (blue and fawn colors)
  • Onset of disease unknown

Partial Albinism
  • First identified in a female Doberman born in 1976.
  • Bred to a dominant black male, then consecutively in-bred with her son to produce an all-albino litter.
  • Became highly in-bred and were introduced into top show bloodlines.
  • In 1982, the AKC determined that albino Dobermans were not allowed to be shown.

Dilution Alopecia in the Doberman

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Partial Albinism in the Doberman

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Normal coat colors in Dobermans (Black and Red)

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Description

Dilution Alopecia
  • Genetic defect that affects the distribution of pigmentation in hair.
  • Blue and Fawn coat colors are most commonly affected.
  • Abnormal melanin pigmentation causes changes in hair color.
  • Severely affected dogs can have stunted hair growth or breakage of hair strands.
  • Extreme cosmetic defect in dogs, no life-threatening health issues.


Partial Albinism

  • Mutation in the tyrosinase gene (an enzyme that is responsible for the conversion of tyrosine to melanin).
  • Reduces the number of pigments in the hair, causing a lighter coat color.
  • The mutation is a "masking gene"; it hides the dog's true genetic coloring.
  • Not considered a true color in Dobermans (4 true coat colors exist - black, red, blue and fawn).
  • Common for dogs with partial albinism to have health and behavioral problems (sensitivity to light and skin issues).

Diagnosis

Dilution Alopecia
  • Initially rule out other problems that may cause hair loss (hormonal or skin disorders).
  • Skin biopsy shows abnormal amounts of melanin and composition of hair follicles.
  • Consideration of breed, color, hair loss and location of hair loss.


Partial Albinism

  • Phenotype consistent with albinism characteristics.
  • Genetic testing for tyrosinase gene mutation.

Treatment and Prognosis

Dilution Alopecia
  • No cure; first priority is to prevent secondary skin infections and potentially stimulate hair regrowth.


Partial Albinism

  • No cure; supportive therapy for secondary health disorders.

Genetic Transmission

Dilution Alopecia
  • Method of transmission is genetically based, but origin is unknown.


Partial Albinism

  • Autosomal recessive gene in Dobermans (c).
  • Not sex linked.
  • Albinism produced if dog contains both recessive copies of the gene (cc).
  • Dog with the gene (Cc) will be of normal color but may produce albino offspring if mated with another dog carrying the recessive (c) gene.

Genotypes and Phenotypes

Dilution Alopecia
  • Genotype of affected dogs unknown.
  • Phenotype appears as fawn or blue coat color with symptoms of hair loss.

Partial Albinism
  • Mating two parents with normal genes for Doberman coat color will produce normal coat colored offspring.
  • Mating two heterozygous parents for the albinism gene will produce a 25% chance of homozygous dominant for normal color in offspring, a 50% chance of heterozygous for the albinism gene in offspring, and a 25% chance of homozygous recessive for the albinism gene in offspring.
  • Phenotype for heterozygous offspring with the albinism gene is any of the four normal coat patterns in the Doberman (depending on parents' genotype).
  • Phenotype for the homozygous dominant offspring will also be any of the four normal coat patterns in the Doberman (depending on the parents' genotype).
  • Phenotype for the albinism gene is a creamy white coat with bright blue eyes and pale pigmentation.

Eradication Methods

For both Dilution Alopecia and Partial Albinism, selective breeding can be practiced to prevent the spread of each disease in the future.
  • Possible genetic testing in parents for prevalence of the disease.
  • AKC denies registration and showing of Partial Albinism Dobermans.
  • Education on genetically inherited diseases to Doberman breeders.

Discussion Point

Due to the unique characteristics of the albino Doberman, breeding for this unusual pale coloring is sought after by consumers and is traditionally in high demand. However, many people are unaware of the detrimental health impacts this has on affected dogs and their overall quality of life. I believe that dog breeders should be closely monitored and be required to have their dogs genetically tested for disorders that could potentially create offspring with physical or mental health issues. Furthermore, I think that breeders who are guilty of purposefully breeding dogs to produce a specific phenotype (Dobermans with Partial Albinism) should be punished with some form of animal mistreatment and should no longer be able to have animals in their care.