White cats, be they shorthaired and sleek like the Khao Manee or longhaired and fluffy like the Chinchilla, are special.
With their brilliant eyes and their pristine coats, these cats often seem to belong to a different species, and they seem untouchable and incorruptible.
There are three main reasons why a cat can have a white coat:
(1) the cat has the white masking dominant gene,
(2) the cat has the white/piebald spotted masking dominant gene, and the spot that cat has just happens to cover its entire coat and
(3) the cat has the congenital disorder known as albinism. It’s obviously difficult to tell why a cat’s coat is white just by looking at the cat, but, fortunately, the cat’s eye color will indicate the reason for its coat’s whiteness.
Cats that possess the white masking dominant gene – the W gene – will always have white coats and will often have blue eyes to go with their white coats.
Should, however, the recessive white masking gene be present – the w gene – and should this gene appear on its own and not along with a dominant W gene, the cat’s coat will not be white but will be the color expressed by whatever other genes it has inherited.
The W gene acts by reducing the number of color-producing cells, melanocytes, in both a cat’s coat and eyes, and the lower the number of melanocytes, the higher the chance of blue eyes.
White, blue-eyed cats also have a higher chance of being deaf, and, even in odd-eyed cats with blue/gold eyes, there’s a chance of their being deaf in the ear alongside the blue eye.
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Cats that have the white/piebald spotted masking semi-dominant gene – the S gene – express this gene in a variety of ways from small white spots to a total white coat.
As the white spotting is not related to a lack of pigmentation, however, these cats’ eyes will not be blue and will rather be orange or green.
The white spotting gene is also not related to deafness.
Albinism is a congenital disorder that manifests in a very small percentage of cats, and it would be a mistake to consider the majority of white-coated cats to be albinos.
The defining characteristic of this disorder is a partial or total lack of pigmentation – color cells – in the animal’s eyes, skin and fur.
Not only do albino cats have white fur, their skin is also extremely pale – and cancer-prone – and their eyes are either extremely light blue, blue-pink or pink.
As mentioned above, blue eyes indicates lower melanocyte levels, and, in albino cats, eyes look pink not because of pink pigmentation but because light is glinting on the blood vessels within the eyes.
There are also several types of albinism, including the temperature-dependent form that causes the colorpoint coat pattern.
Many factors have to come into alignment for a cat to have a white coat, but, when they do, the result is always spectacular!