Test for the champagne dilution of the SLC36A1 gene, which lightens the coat and skin and produces light eyes and unpigmented hooves. Complementary to, not a substitute for, clinical examination.

Applicable breeds: American Cream Draft, American Miniature Horse, American Paint, American Saddlebred, Appaloosa, Quarter Horse, Tennessee Walking Horse and others. Frequencies: limited data.

• Lightening of the coat over any base color (classic, golden or amber champagne).\n• Pink or mottled skin and light hooves.\n• Light eyes (green/amber) with greater sensitivity to light.\n• The pigment does not disappear completely; the tone is warm.

Champagne was mapped to chromosome 14, and in 2008 Cook and colleagues identified the causal mutation in SLC36A1 (c.188C>G, p.T63R).

• Avoid pairing two champagnes if the phenotype is not sought, although homozygotes do not appear to have serious consequences.\n• Interpretation must take the base color into account (extension/agouti).\n• Do not confuse champagne with cream, pearl or silver.\n• A negative result does not rule out other dilutions.

Champagne is usually accompanied by cutaneous mottling and light eyes; consider protection from light. Differential diagnosis from pearl and double dilution of SLC45A2.

1. Cook 2008, Missense mutation in exon 2 of SLC36A1 responsible for champagne dilution in horses (PMID 18802473); OMIA:001263-9796.