White Cats and Deafness

Albino cats are also white. True albinism causes pinkish eyes, but some albinos or partial albinos have pale blue eyes. There are too few albino cats studied to draw firm conclusions, but this mutation is not necessarily linked with deafness. It is also hard for a cat owner to determine whether their cat is a blue-eyed albino cat rather than an ordinary blue-eyed white.

There is also a gene for blue eyes which is inherited separately from coat color. This is the gene responsible for the Ojos Azules breed. If the cat is white colored, there is no easy way of telling whether it has the blue-eyed-deaf-ear type gene or the Ojos-Azules-blue-eyes type gene. It's only possible to tell that a cat has this particular gene if the cat is non-white and has blue eyes.

Genes for blue eyes independent of coat color may be more common than previously realized. I have encountered three blue-eyed random-bred cats (one ginger, one silver tabby, one brown tabby) in one UK town between 1989 and 1995. This may be the same gene as Ojos Azules, or it may be due to different gene mutations. Other types of blue eye are being discovered in all-white cats in Asia, the blue is different than Siamese Blue Eyes, but does not seem to cause deafness.

The white coat can be caused either by a gene for white coloration or by a gene for 'white patching' - sometimes the white patching is so extensive that the cat appears solid white. If the white cat exhibited a few colored hairs or a smudge of color on its body (usually on the head) as a kitten, then it should have normal hearing even if it has blue eyes because it has inherited a non-deafness causing gene for white coat!

Blue-eyed bi-color cats occur and the more white they have in the region of their eyes and ears, the more likely they are to be deaf. This is because one of those genes for white affects the development of both the eyes and ears - it causes lack of eye pigmentation (i.e. blue eyes) and deafness - and since the eyes and ears are close together, if that gene affects that area of the body, it is likely to affect both sense organs (hence odd eyed whites may be deaf on the blue-eyed side).

Congenital deafness can also be caused by a variety of hereditary factors, just as in humans. Due to random mutation or the wide gene pool, cats of any color can be born deaf (probably less than 1%) - including orange-eyed whites. Hence deaf white cats with non-blue eyes can occasionally appear and in these cases the deafness is not linked to coat color. Deafness can also be caused by illness or injury, so a person adopting a deaf cat may not know whether the cat was born that way or became deaf later on.

(Continued on next page)