Opinion on Pigment - Page 3

Why do we care about pigment? We care about "pigment" to avoid albino related problems (blindness, deafness etc.). "Color" is something different. A Samoyed which has a white coat may or may not have albino traits. The same for a blue eyed Siberian Husky.  Until recently "red" marking in GDS was so much in demand that many breedesr actually "painted" them (so much so that now the SV is cutting hair and testing for paint.)
Fadling color gives you an an early warning signal. But take it as it is: a warning: you have time for action.
For actua, more seriousl problems, focus on nails, nose and eyes.

The white shepherd breeders seem to be keeping up well with the latest scientific revelations in color.  Just bear with the fact that because it's based on biological science and not breed judging definitions, pigment ALSO refers to the coloring in hair follicles.

The Genetics of Coat Color in the White (German/Swiss) Shepherd Dog
By Michael Handley
 

Agouti (A) alleles and MC1R (E) alleles each create chemicals that compete with each other to regulate pigment function in hair follicle melanocytes:
 

• alleles of the Melanocortin-1 receptor (MC1R) gene code for variations of Melanocyte Stimulating Hormone (MSH) which regulate eumelanin (brown/black) pigment production in hair melanocytes, and 

• alleles of the Agouti (A) gene code for variations of Agouti Signal Peptides (ASIP) which regulate the density, distribution pattern and exact color palette of eumelanin (brown/black) and phaeomelanin (yellow/red) pigment that melanocytes then inject into hair fiber.

The regulatory competition between each variation of ASIP and MSH is the mechanism that forms German Shepherd coat colorations ranging from the classic German Shepherd sable coat colors all the way to a solid black coat color.

The MC1R gene, historically called the Extension (E) gene, even has an allele that codes for a version of MSH that does not switch on the eumelanin pigmenting processes within hair follicle melanocytes, thus leaving no eumelanin for the Agouti (A) gene alleles to regulate. Another gene, as yet undiscovered by genetic researchers, is thought to regulate phaeomelanin (yellow/red) pigment production in a manner similar to the MC1R eumelanin regulating function. Alleles of yet another gene, or genes, such as the Melanophilin (MLPH) “pigment clumping” gene*, can further vary function in melanocytes to modify color.9Genetic science has not yet identified, through genetic testing, all of the genes and alleles responsible for the regulation for coat hair color.

* - Function of the Melanophilin (MLPH) “pigment clumping” gene has historically been attributed to the Dilution (D) gene. The blue coat phenotype (also sometimes described as charcoal grey) is often described as a “dilution” or “paling” of the black coat color. This so-called “dilution factor” has historically been mapped to gene (D) and is known to cause the clumping of pigment granules in hair fibers. Genetic research has recently shown that the blue coat pigment clumping condition is caused by an allele mutation of the Melanophilin (MLPH) gene.9 In the German Shepherd Dog this gene acts in combination with Agouti (A) and MC1R (E) alleles to form the blue coat color.