Acromelanism

It is commonly known for the coloration of Siamese[1] and related breeds of cat, but can be found in many other species including dogs, rabbits, rats, mice, guinea pigs, minks, and gerbils.

Colorpoint patterns are where the extremities (paws, face, ears and tail) of the animal are colored differently compared to the rest of the body.

Colorpoint patterns occur due to acromelanism, which is a type of partial albinism where pigmentation is affected by temperature.

The mutated enzyme is thermolabile; it fails to work at normal body temperatures, but becomes active in cooler areas of the skin.

[3] As the expression of the gene responsible for the pointed pattern is regulated by temperature, pointed cats who live in cooler environments often show increased darkening of their fur relative to cats who live in warmer climates; in some extreme cases the entire coat will darken.

It is characterized by a mixture of the darkening (reduced) of point coloration with distinct tabby striping on the head, tail, and legs, and an otherwise uniform and comparatively pale body.

[7] Recent documented evidence about acromelanism in dogs has only existed since 2017, when the first colorpoint dachshund was reported in the Czech Republic.

Genotyping the aforementioned dachshund revealed a mutation in the tyrosinase gene that results in a recessive colorpoint allele.

[citation needed] The resulting point coloration is sometimes in conjunction with a coat pattern, such as: white agouti, marten, broken, Vienna, or harlequin.