Test Detail

Test for the cream allele of the SLC45A2 gene, responsible for the palomino, buckskin, cremello and perlino phenotypes. Complementary to, not a substitute for, clinical examination.

Applicable breed: Quarter Horse, Morgan, Welsh Pony, Pura Raza Española, Icelandic and many others. Frequencies: limited data.

• Heterozygosity: lightens pheomelanin (chestnut) and produces palomino or buckskin; black hair may be retained.
• Homozygosity: lightens both pigments and produces cremello (on chestnut) or perlino (on sorrel/black).
• Light skin and blue eyes in double dilutes.

The cream locus was mapped to chromosome 21 and in 2003 Mariat and colleagues identified the mutation in the MATP gene (now SLC45A2) responsible for the cream/palomino color.

• Avoid cream × cream if a double dilute is not sought; the double dilute may be associated with hearing loss and greater skin sensitivity.
• Selection for palomino/buckskin requires knowing the base color (extension/agouti).
• Do not confuse cream with champagne, pearl or silver.
• A negative result does not rule out other dilutions.

Double dilutes (cremello/perlino) show less ocular pigmentation and may have greater photosensitivity; assess hearing if suspected. Interpretation depends on the melanocytic genetic background.

1. Mariat 2003, A mutation in the MATP gene causes the cream coat colour in the horse (PMID 12605854); OMIA:001344-9796.
2. Holl 2019, SLC45A2 variants explain dilute phenotypes, pearl and sunshine (PMID 31006892); OMIA:001344-9796.