Most horses that appear white are actually "grey", meaning they were born another color and then turned grey as the pigment was gradually eliminated by the "grey" gene.
Cremello "White" horses are pink-skinned and blue-eyed.
"Dominant White" is a genetic allele that produces a pure white horse with dark eyes.
This is an uncommon gene, however, though there are horse breeders who specialize in it.
Horses that appear white may be cremello, gray, perlino, ivory champagne, "Dominant White, or an extreme form of one of the appaloosa or pinto patterns, in which the colored areas are so small as to be virtually undetectable.
The "Dominant White" gene is a dominant allele that is rather rare and was formally believed not to exist. But it does occur occasionally. A Dominant White horse has normal-colored eyes and pure white hair. Skin color is variable. There is now a genetic test for Dominant White, read about it by clicking here.
Please note that, despite common usage of the term, true "Albino" horses do not exist, or have never been documented to exist.
A true Albino would have pink eyes - albinism is the total lack of any pigment, including the skin and eyes. Look at an albino rabbit or mouse to see a true albino animal. Horses called Albino are usually Cremello - which is a pale cream color with blue eyes, or Maximum Whites - again, with blue, not red or pink eyes.
This foal, owned by Tammi Vogel, is alive today thanks to information Tammi was able to learn from this website! When the pure white foal was born, he seemed normal, but local hore folks all warned that it was only a matter of time until symptoms would start and he would die a painful death - so she should call the vet out and have the foal put down.
Tammi made the vet appointment but luck was with her and the vet couldn't come out until much later. During that time, she researched Lethal White on the Internet and came upon this website, where she learned of Maximum White Overos - in this case, Maximum Sabino, judging from the mother's lacy spotting pattern.
I happened to check my email early that morning and my heart jumped to my throat when I saw the photo and the diagnosis. DON'T PUT THAT FOAL DOWN! I responded and called her on the phone. We had a nice conversation and she was very relieved to be able to give the foal a chance.
Three days later he was still fine, so the vet never needed to come out to do the dreaded deed.
Many months later, "Go Check Whitie" (named for the frequent text message Tammi sent to her family while she was away at work) is healthy and strong, a completely normal weanling colt!
RARE & MISCELLANEOUS: BRINDLE BROWN CHROME CURLIES WHITE DUN OR BUCKSKIN? CHIMERAS AND SOMATIC MUTATIONS
GENETIC OVERVIEW EQUINE BASE COLORS DOMINANT GENES DILUTION GENES RECESSIVES