Deafness

Patty Khuly

Summary

Hereditary deafness is a relatively common condition in certain breeds and/or lines of dogs and cats. It usually occurs as a result of degeneration of sensory nerve-related inner ear structures within a few weeks of birth but can also occur congenitally, meaning it is already present at birth.

Sometimes this trait is associated with others, as when it’s inherited along with genes that specify a white or merle coat color and/or blue eyes.

The mode of inheritance of this disorder has not been established. In fact, the one thing we do know is that deafness in does not follow a specific pattern of inheritance. Currently, the entire canine genome is being studied to help determine the genes that might be associated with this trait. Pigment genes are being targeted as a result of an obvious correlation between coloration and deafness.

This trait may be inherited unilaterally or bilaterally. As a general rule of thumb, unilaterally affected dogs live perfectly normal lives while bilaterally deaf animals can suffer major behavioral problems if owners are not willing to take special steps to train these dogs appropriately. By contrast, bilaterally affected cats typically lead near-normal lives as indoor pets.

Symptoms and Identification

Bilaterally deaf dogs are normally identified early on in life––usually because they sleep deeply as puppies or play too rough with their littermates (as when they fail to hear their mates’ cries).

Definitive diagnosis is usually achieved via Baer testing which requires specialized equipment typically available only through veterinary neurologists.

Affected Breeds

Approximately 30 percent of all Dalmatians and 14 percent of English Setters in the United States are reportedly born deaf in at least one ear. Australian Shepherds, Border Collies and Shetland Sheepdogs also suffer a high incidence of deafness.

Increased areas of merle, piebald and white coloration is associated with a higher risk of deafness. In addition to the breeds listed above, this includes the Australian Heeler, Dapple Dachshund, Harlequin Great Dane, Norwegian Dunkerhound, Old English Sheepdog, Beagle, Bull Terrier, Samoyed, Great Pyrenees, Sealyham Terrier, Greyhound and English Bulldog.

Congenital deafness is seen in the Akita, Cocker Spaniel, Staffordshire Terrier, Boston Terrier, Boxer, Catahoula Leopard Dog, Doberman Pinscher, Dogo Argentina, English Springer Spaniel, Foxhound, German Shepherd, Greyhound, Jack Russell Terrier, Kuvasz, Maltese, Miniature Pinscher, Miniature and Toy Poodle, Papillon, Rhodesian Ridgeback, Rottweiler, Saint Bernard, Scottish Terrier, Shropshire Terrier, Siberian Husky, West Highland White Terrier and Whippet.

Treatment

There is no accepted means of treatment for hereditary deafness in dogs and cats but dogs and cats so affected will often have a higher quality of life if they receive specific training utilizing hand-signals (among other approaches).

Veterinary Cost

The cost of diagnosis is typically relegated to the normally sub-$300 Baer testing required to establish the diagnosis. Specialized training, however, can be expensive if high-quality professionals are employed.

Prevention

Removing bilaterally or unilaterally affected individuals and carriers of this trait from the breeding pool is the only known means of prevention. Genetic testing for deafness is being researched for dogs but is not yet available to help screen for this trait. Baer testing is strongly recommended for all Dalmatians and English setters prior to breeding.



References

Ackerman, L. 1999. The Genetic Condition: A Guide to Health Problems in Purebred Dogs. pp 132-133. AAHA Press. Lakewood, Colorado.

Wood, J.L.N., Delauche, A.J., Lakhani, L.H. 1996. The problem of inherited disease 6: deafness in Dalmatians. J. of Small Animal Practice. 37(11) : 559-561.