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I was told that all pure white cats with both eyes being blue are completely deaf, and that all pure white cats with one blue eye are deaf on the side that has the blue eye.

If the cat has even a single spot on it it is not considered pure white.

Google presents me with contradictory answers to this question.

Please help me settle an argument.

Thanks

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Welcome to Skeptics! We want to focus our attention on doubtful claims that are widely held or are made by notable people. Please provide some references to places where this claim is being made. –  Oddthinking Jun 28 '12 at 8:11
    
Ho do I reference an offline conversation? –  darryn.ten Jun 28 '12 at 8:48
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If you are just referencing your mate, in the pub, that isn't notable. But you suggested you found some other places on Google. Link to them, and include some example quotes, please. –  Oddthinking Jun 28 '12 at 9:47
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1 Answer

up vote 23 down vote accepted

NO, not all pure white cats with blue eyes are deaf, however:


From FabCats:

In cats, congenital deafness is seen almost exclusively in white coated individuals.

The deafness is caused by degeneration of the auditory apparatus of the inner ear and may affect one ear (unilateral) or both (bilateral).

Breeding studies have defined the relationship between deafness in white cats and blue eye colour.

The gene responsible is autosomally dominant gene W with complete penetrance for white coat colour, with incomplete penetrance for deafness and incomplete dominance for blue iris colour. The variable penetrance of deafness and eye colour may be caused by interplay with other genes or environmental factors.

Cumulative studies from various countries have found:

Cats


References:



From Deafness in blue-eyed white cats (by George M. Strain, Louisiana State University):

[Pure white cats with blue eyes] are well-known to be commonly affected by a congenital hereditary deafness that may affect one or both ears; the deafness is linked to the so-called W gene.

Reports of this condition date back to at least the 1930s (Bamber, 1933), and many investigators have studied it in subsequent years:

[...]

Delack (1984)1) analyzed three studies of deafness in nonpure breed white cats that included a total of 256 cats (Bosher and Hallpike, 1965; Mair, 1973; Bergsma and Brown, 1971);

  • 12.1% were unilaterally deaf and 37.9% were bilaterally deaf, or a total of 50% were affected.

  • When cats that were the offspring of two white parents were examined, the prevalence of deafness (unilateral or bilateral) ranged from 52% to 96%.

1) Delack, J.B., 1984. Hereditary deafness in the white cat. Compendium on Continuing Education for the Practicing Veterinarian 6, 609–619


Two of the studies (Mair, 1973; Bergsma and Brown, 1971) examined the effect of blue eye colour on deafness, finding (respectively) a prevalence of deafness (unilateral and bilateral combined)

  • of 85 and 64.9% in cats with two blue eyes,

  • 40 and 39.1% in cats with one blue eye,

  • and 16.7 and 22% in cats with no blue eyes.

So, not all white cats are deaf and not all blue-eyed white cats are deaf, but a great many of them are so-affected.


More:

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It's interesting seeing the hereditary linkage. As a child, we had a white cat with blue eyes who had kittens about every 6-8 months, and about 20% of the kittens were also white with blue eyes. None were deaf. So I had questioned that claim about white cats/blue eyes and deafness. But the explanation above makes sense. –  thursdaysgeek Jun 29 '12 at 23:07
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