White Patterns in Cats
At the present time there are at least three (3) white spotting patterns in cats. These are Dominant White (W), Piebald Spotting (S), and White Gloves (G). These white patterns can be found alone, or with other white patterns. They can also be found with any combination of dilutions and/or modifiers.
White norwegian forest catWiki Commons
Dominant White (also known as White Masking) is a white pattern found in cats that causes the cat to be solid or almost solid white. As its name suggests it is a dominant mutation. Cats that are WW or Ww will be white while cats that are ww will express normal coloring. Since Dominant White masks all other coat colors and patterns it cannot be determined what genes these cats carry without genetic or breeding tests. Cats that are Dominant White can be found with blue, green, yellow, or bi-colored eyes and white cats can be deaf. The deafness is thought to be caused by lack of pigmentation in the inner ear caused by the white pattern. Not all cats with Dominant White are deaf however. White cats that have yellow or green eyes are much more likely to have normal hearing than blue eyed white cats. This is because blue eyes in white cats are generally caused by a lack of pigmentation in the eye which is very close to the inner ear. Careful breeders do not breed from deaf cats in an attempt to produce only cats with normal hearing. This had reduced but not eliminated the number of deaf Dominant White cats. It is still possible for two white cats with normal hearing to produce deaf offspring because it is not known what controls the extent of white markings although it is known to be at least partly hereditary.More Dominant White Images
An example of Piebald Spotting in catsWiki Commons
Piebald SpottingPiebald Spotting is thought to be a semi-dominant mutation. This means that cats that are SS will display more white than cats that are Ss. Cats that are ss do not carry the Piebald mutation but may still have white caused by other mutations. Piebald can cause a greatly varying amount of white. In minimal form it is thought to be able to cause just white paws or white paws and a white nose. These cats would be Ss (Heterozygous) for Piebald Spotting. In maximal form the pattern is sometimes called Van. Van cats will be mostly white and rarely completely white. Van cats are thought to be SS (homozygous) for Piebald Spotting. When this amount of white expresses, deafness can occur as with Dominant White cats. Piebald can occur with other white patterns or any other modifiers or dilutions.
An Example of White Gloves in a Birman KittenWiki Commons
White Gloves is a kit gene mutation that has been found in Birman cats, their crosses, and (at low frequncey) in other breeds with Birman influence. It is a recessive mutation meaning that cats must carry two copies of the mutation in order to express White Gloves. Although, cats with two copies of this mutation will have white gloves, not all cats with white gloves carry the White Gloves mutation. These cats many be minimal Piebalds or many carry a yet unknown mutation. Cats with White Gloves will generally have four (4) white feet.