Horses do not have the true albino gene, which is a recessive gene that suppresses all pigment in the coat, skin and eyes. Some breed registries call white or near-white horses albinos, but the coloring of these animals comes from different genes.
Most white horses arise from mutations on a gene known as KIT. There are 11 separate lineages of horses with white color arising from spontaneous KIT mutations. One of the best-known one descends from a thoroughbred mare named White Beauty foaled in 1963; one of her descendants, Chief White Fox, won a race in 2013. KIT mutations causing white coloring are called "dominant white" because the gene is a dominant one that is passed down from parent to foal and does not skip generations.