The cream dilution gene affects base colors by lightening them, a single dilution of the gene produces colors like palomino and buckskin. While a double dilution creates the red-eyed and light-skinned cream colors often mistaken for albino (which doesn’t exist in equines).
This gene has a lightening effect on the hair and is responsible for a hugely varied scope of colors. The most obvious effect is on chestnut and bay animals, a single dose changes their coats to a golden or tan color. While it can have an effect on black coats, it usually requires a double dose.
Single Dilute Cream Shades
A single cream gene has a rather dramatic affect on chestnut bases, creating some of the most sought after colors. Note that only in chestnut horses is the mane and tail hair affected.
This coloring is also called Isabella and caused by one dose of the cream gene on a chestnut base and ranges in shades from cream to deep red gold. Palominos are generally born light and grow darker as they age and eyes can be hazel, green or even blue. Skin is generally dark, but can also be light.
This coloring is often incorrectly interchanged with dun which is entirely different genetically. Caused by one dose of the cream gene on a bay base, usually only body hair is affected turning it anywhere from creamy white to deep golden yellow. Mane, tail and points remain black or dark brown and can fade with age.
Double Dilute Cream Shades
A double dose of the cream gene affects colors much more dramatically and can even make black animals almost pure white. Double cream dilutions are the most often mistaken for albinos (again, which don’t exist in horse genetics).
Perhaps the lightest of the bunch, cremellos are caused by a double dose of the cream gene on a chestnut base. They always have pink skin and blue eyes and their coat color varies from bright white to dark cream.
Perlino is a double dose of the cream gene on a bay animal and often difficult to tell from cremello. Their mane, tail and points will be darker than the body hair and often have a reddish tinge to them. Perlinos always have pink skin and blue eyes and their coat color varies from bright white to dark cream.
A double dose of the cream gene on a black base has a rather dramatic affect on their color. All hair can be lightened from white to dark cream.
Animals can carry more than one dilution gene, (or modifier for that matter) furthering the rainbow of colors & patterns that can be found. Here are some examples.