Is it true that white cats with blue eyes can be deaf? White fur cats with blue eyes are perhaps the most beautiful that we can find, but it is also true that they are usually deaf and the reason seems to be in a gene that although it is responsible for the color of their fur and eyes, so is, unfortunately, his deafness.
Is it true that white cats with blue eyes can be deaf?
In cats, inherited congenital deafness (present from birth) is something that usually occurs mainly in those with white hair and blue eyes. The cause of their deafness is none other than degeneration of the hearing system of the inner ear and can affect one ear (unilateral) or both ears (bilateral).
Breeding studies have defined the relationship between deafness in cats that are white and blue-eyed . The responsible gene is an autosomal dominant gene called W (for White) . This gene appears to be pleiotropic, that is, it has more than one effect , being responsible for the color of the white fur and blue eyes, but also for deafness.
However, while the gene has full penetrance for white fur color (all cats carrying the gene will have white fur), it has incomplete penetrance for blue eye color and deafness (although these two are strongly linked). Therefore, deafness is strongly related to white fur color and blue eye color, but not all white cats or white cats with blue eyes are necessarily deaf. The variable penetrance of deafness and eye color may be due to interaction with other genes and / or environmental factors.
What is the risk of deafness in a white cat?
In general, deaf cats that have white fur and one or both blue eyes, account for about 1-1.5% of the total cat population. However, the prevalence of white cats varies in different geographies.
If a white cat has 2 blue eyes, it is 3 to 5 times more likely to be deaf than a cat with eyes of another color, and a cat with 1 blue eye is approximately twice as likely to be deaf before a cat with different colored eyes. Additionally, long-haired white cats are 3 times more likely to be bilaterally deaf . And in a wild situation, deaf white cats experience a strong negative natural selection pressure since in addition to being deaf they are also photophobic (intolerant of bright light due to blue eyes)
and have reduced vision in low light conditions.
However, among domestic cats it is much more common to find white cats , probably simply due to selective breeding (preferably and human intervention) although with that risk that they are deaf. For this reason, cat breed experts insist that white cats be screened for deafness (for example, by the BAER brainstem auditory evoked response test, which is a simple, non-invasive test that can be performed in specialized centers for accurately determine if there is deafness) and in particular, not allow the reproduction of deaf white cats.