Deafness/ White pigmentation

I have been told that the gene that controls white pigmentation in bull breeds also correlates to the gene for deafness. I.E. more white, more chance of hearing loss. Anyone else heard this, or is it wives tale?

 

Some people refer to mostly white deaf dogs as "albino" or "part-albino." The term albino is often used as if it just means "white," but the facts are somewhat more complicated. In actuality, there are degrees of albinism (although "part" albino, i.e. white with patches of full pigment, is not possible). A "complete" albino (pure white) has no pigment (not even skin spots). Their skin is a very pale pink, and their eyes are usually pink as well (this is called tyrosinase-negative). Even though this is what is usually thought of as albino, dogs with this genetic pattern are very rare, and likely to be deaf (since they have no pigment at all). There are other forms of albinism (called tyrosinase-positive) that are not really white (they will be an even all-over light gray or pale cream instead). The West Highland White Terriers and white Dobermans fall into this category. Since these dogs do have pigment, they are not usually deaf (see Causes of Deafness above.) To read more on this subject, see Coat Color Genetics (a bit technical, but albinism is discussed) or White Dobes (really technical).

There are many genetic factors that can cause a dog to have a lot of white in its coat (try looking at Dog Genetics Links On the Web for more information on various breeds). Many dogs will have more than one factor at work as well.



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What causes a dog to lose its hearing? A lot of the same things that cause hearing loss in humans. Genetic defects can cause a dog to be born deaf; this is known as congenital deafness. A dog can also lose its hearing due to an ear infection, injury to the ear, or may experience gradual (or sudden) hearing loss due to old age. Exposure to loud noise can cause temporary or permanent hearing loss, as can certain drugs.

The most common cause of congenital deafness is pigment related. (There is some talk about a recessive gene as well, but most researchers do not believe this is the case.) Some dogs have white coats, but still have pigmented skin (Samoyeds, West Highland Terriers, and White German Shepherds fall into this category). Although they have white fur, they have black noses and eye rims (their fur is actually not pure white, but a very light buff color). Other dogs normally have colored coats, and white trim (this includes Dalmatians; the white is actually not their real coat color, the "spots" are). The "trim" comes from areas of unpigmented (pink) skin, which produces white hair. If there is unpigmented skin in the inner ear, the nerve endings atrophy and die off in the first few weeks of the puppy's life, resulting in deafness. Please note that you cannot tell the color of hairs in the inner ear by looking at any visible part of the dog's ears (including the hair around the ear canal). Although many dogs with white hair on their ears will be deaf, many deaf dogs have colored ears as well.

Hearing loss affecting both ears is called Bilateral Deafness. A bilaterally deaf dog is completely (or mostly) deaf in both ears. Hearing loss occurring in, or affecting only one ear, is called Unilateral Deafness. A unilaterally deaf dog has hearing loss in only one ear and has full hearing in the other ear.

 

So other than fairly rare cases, white pits are not normally deaf. Thanks , once again this site and its members have proven themselves to be top of the yard.

 

Great post!..........Thanks