Deaf White Cat Syndrome

The Correlation Between White Cats and Deafness

What is Deaf White Cat Syndrome?

It is thought that the prominent characteristic of deafness associated with white coat color and blue eyes stems from the breeding of white British shorthaired cats and blue-eyed Siamese to produce offspring with a desirable phenotype of white fur and blue eyes. Ultimately, the gene that is responsible for white fur, W, is also the gene in which deafness arises from.


Deafness in white-coated cats is seen nearly exclusively and is caused by degeneration of inner ear. This degeneration can occur in the womb, shortly after being born, or even years after being born. The deafness may occur in one ear (unilateral), or in both (bilateral). Interestingly, it is found that if a cat has one blue eye and one non-blue eye and deafness occurs in only one of the ears, the ear that is deaf will be on the same side that the blue eye is on.


A majority of the time most pet owners are unaware that their cat may be deaf in one ear. And even if the cat is completely deaf, some indoor pets are able to function and live normally. However, for most cats it is incredibly difficult to have no hearing senses. Due to the fact that cats rely heavily on the senses of hearing, sight, and smell, if a cat is without one of these it decreases it's chances of survival greatly. Without the ability to anticipate, react, and respond to their environments most cats are found in very deadly and dangerous situations such as, getting hit by a car or attacked by a dog. The odds of these circumstances occurring increases greatly when looking at the deaf feral cat population.

Transmittance and Probability

Deaf White Cat Syndrome is caused by an autosomal dominant gene (W) which causes white fur, and in some cases blue eyes and/or deafness. Not all cats with white fur or with white fur and blue eyes are deaf. However, the likelihood of a cat being born or becoming deaf if they have white fur or white fur and blue eyes dramatically increases. Research has found that 17 to 22 percent of cats born with white fur and non-blue eyes are deaf. The percentage rises to 40 percent if the cat is born with white fur and one blue eye and one non-blue eye. Expectedly, the percentage increases upwards of 65 to 80 percent if the cat is born with a white coat and two blue eyes.

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General Appearance of Deaf White Cat Syndrome

Since the gene that is responsible for a white coat is dominant (W), the genotype of white cats is either going to be homozygous dominant (WW), or heterozygous dominant (Ww). As a result, the cat will have a white coat. Keep in mind that not all white cats are deaf, but the odds of having a white deaf cat greatly increase because deafness results from effects on the W gene.

Prevention and Diagnosis

There are several breeds of cats that are known to carry the W gene. As a result, these cats all have the potential of producing white deaf offspring. Before breeding a cat that may be affected, it should first be checked for deafness using BAER testing. This is a brainstem auditory evoked potential test which will detect brain activity when exposed to different sound stimulation. BAER testing is not painful, and does not take much time. This procedure occurs in the same fashion for both dogs and cats. Some pet owners may not know when they adopt their cat that it may be deaf, but as the cat matures signs may become evident that he or she is deaf. For example, not waking up as the owner approaches or having abnormal meowing. Below are videos of a deaf cat meowing, a deaf cat being woken up, and a puppy undergoing the BAER test.
Amazing Super Loud Cat!!! How do you know your cat is deaf: Video 1
Waking a Deaf Cat Part 2 WAKE UP !!!
Summit Dalmatians, Wilson/Baer hearing test

Personal Opinion

I think it is extremely important to test not only cats that may show signs of deafness, but to test cats who are white, and who are white with blue eyes. If the results conclude that the animal is deaf then I think immediate action should be taken to spay/neuter the animal. It is such a danger for cats to be without their sense of hearing, and I don't think it is responsible pet ownership to allow an animal the possibility of breeding and creating more of the problem. However, I don't think it is necessary to euthanize an animal just because it is deaf. Deaf animals can have a good quality of life, but I think prevention should be used to ensure that the breeding of animals is kept safe and allows the possibility for the best quality of life for the offspring.

References

Bergsma, Donald R., et al. "White Fur, Blue Eyes, and Deafness in the Domestic Cat." Journal of Heredity 62.3 (1971): 171-183. Oxford Journals. Web. 19 Apr. 2013.


Cornell Feline Health Center. Cornell University College of Veterinary Medicine . 2 April 2013 <http://www.vet.cornell.edu/fhc/askdr/deaf.cfm>.


Dourmishev, Assen L., et al. "Waardenburg syndrome." International Journal of Dermatology 38.9 (1999): 656-663. Academic Search Premier. Web. 18 Apr. 2013.


Feline Advisory Bureau. Fabcats. May 2010. 12 April 2013 <http://www.fabcats.org/breeders/inherited_disorders/neurological.php>.


Heid , Silvia, Rainer Hartmann, and Rainer Klinke . "A model for prelingual deafness, the congenitally deaf white cat – population statistics and degenerative changes." Hearing Research 115.1-2 (1998): 101-112. ScienceDirect. Web. 21 Apr. 2013.


Strain, Dr. George M. Cat Breeds With Congenital Deafness. 5 November 2009. 5 April 2013 <http://www.lsu.edu/deafness/catbreeds.htm>.