of 15 have a melanoma tumor. Diluted coat colors True white hair is rooted in unpigmented skin that lacks melanocytes. In contrast, diluted coat colors have melanocytes, but vary due to the concentration or chemical structure of the pigments made by these pigment-producing cells, not the absence of the cells themselves. There are at least five known types of pigment dilution in horses, three which, as described below, can act to produce off-white phenotypes. Horses with strongly diluted coat colors usually have pale eyes (usually blue), cream-colored coats, and rosy-pink skin that contains a minimal amount of pigment. White markings are usually visible upon closer inspection. The Cream gene produces two types of diluted color. Horses with fully diluted colors, called Cremellos, perlinos, and smoky creams have rosy-pink skin, pale blue eyes, and cream-colored coats that can appear almost white. These coat colors, collectively called "double dilutes" or "blue-eyed creams", result when a horse is homozygous for the cream gene. The creme gene is an incomplete dominant, as when heterozygous, the dilution is less intense. In these cases, cream is responsible for palomino and buckskin. A few Palominos have a very light hair coat is occasionally mistaken for either cremello or white. White markings and patterns are visible against the slightly-pigmented coat and skin. The cream gene is not known to be associated with any health problems. Pearl-Cream pseudo-double dilute occurs when a horse has one cream gene and one pearl gene. These two distinct dilution factors interact to produce a cremello-like coat. Pearl-creams have pale but pigmented skin and blue-green eyes, and are distinctly pale cream-colored. To date, the Pearl gene has been found in Quarter Horses, Paint horses, and some Iberian horses. Pearl is not known to be associated with any health problems. Champagne-Cream pseudo-double dilute occurs when a horse has one cream gene and one champagne gene. Champagne and cream are another pair of unrelated dilution factors that interact to produce a cremello-like coat. Champagne-creams have freckled, pinkish skin, pale eyes, and pale coats. These colors were formerly referred to as "ivory champagnes". Champagne is found in North American breeds such as the American Cream Draft, Tennessee Walking Horse, American Saddlebred, American Quarter Horse, and Miniature horse. It is not known to be associated with any health problems. Albinism Although white horses are sometimes called "albino" there are no reported cases of a true "albino" horse. There