Blue/Silver (Coat colour D-Locus Dog)

• Depending on the base colour, certain dilution effects occur, resulting in a lighter colour of the dog.
• Hair, but also the skin, have a dark to light grey shade with a special shine up to a bluish shimmer.
• The thinning effect is caused by a mutation in the MLPH(melanophilin) gene.
• The gene is involved in the transport of melanocytes, the pigment-forming cells.
• A mutation-related failure leads to disorders in the pigmentation of skin and hair.
• Dilute' animals are very popular among dog buyers because of their special coat colour.
• However, the dilute mutation can also lead to severe health problems.

Colour Dilution Alopecia (CDA - dilution colour-related hair loss)

also known as: BDS (Blue Dog Syndrom)

Symptoms and information:

• Gradual onset of dry, dull and poor coat quality.
• Increasing hair loss is usually most severe on the dorsal part of the body.
• Skin lesions usually develop slowly with age.
• First clinical signs usually occur between 3 and 12 months of age, rarely later in life.
• Histologically, the hair follicles are characterised by atrophy and deformation.
• Heavily clumped melanin is present in the epidermis, dermis and hair follicles.
• Dogs severely affected by CDA have a significantly lower quality of life due to the poor skin condition.
• The severity of CDA depends on the breed:
  • In breeds such as the Doberman and Newfoundland, the dilution colour type is prohibited.
  • In e.g. Pinscher breeds and Rhodesian Ridgebacks, the reported coat quality in dogs with dilution ranges from normal to severely affected by CDA.
  • Breeds such as the Weimaraner do not show CDA despite dilution colour type. Here the dilution colour is even a breed trait.

Locus Information: D-Locus

This test shows a non-coding c.-22G>A mutation in the MLPH gene.

Test in Shop

Also in the:

• Labrador Retriever B package (DRC P3)
• Coat colour Retriever package (DRC P5)
• Coat colours Eurasier package
• Doberman 1 package

Inheritance: autosomal recessive

→ Only animals with two copies of the mutation (dd) have a lighter "diluted" coat colour and are affected by CDA depending on the breed. Animals with only one copy or without mutation do not show the colour.

Genotypes

D/D = Two functional copies

There is no dilution effect, the dog does not have the colour blue/silver.

D/d = One copy intact and one copy non-functional

There is no dilution effect, the dog does not have the colour blue/silver. The d allele for dilution/CDA is passed on at 50%, the dog is a carrier.

d/d = Two copies non-functional

A dilution effect occurs, the dog has the colour blue/silver. The dog can be affected by CDA depending on the breed.

Welle, M; Philipp, U; Rufenacht, S; Roosje, P; Scharfenstein, M; Schutz, E; Brenig, B; Linek, M; Mecklenburg, L; Grest, Paula; Drögemüller, M; Haase, B; Leeb, T; Dögemüller, C (2009). MLPH genotype—melanin phenotype correlation in dilute dogs. Journal of Heredity, 100(Supplement):S75-S79. https://doi.org/10.5167/uzh-154429

Philipp, U., Hamann, H., Mecklenburg, L., Nishino, S., Mignot, E., Gunzel-Apel, AR., Schmutz, SM., Leeb, T.: Polymorphisms within the canine MLPH gene are associated with dilute coat color in dogs. BMC Genet 6:34, 2005. Pubmed reference: 15960853. DOI: 10.1186/1471-2156-6-34.

Further information is available at Online Mendelian Inheritance in Animals.