Common Symptoms
Early Onset Adult Deafness (EOAD) is an inherited disease resulting in progressive loss of hearing in affected Rhodesian Ridgebacks. Affected dogs can present as early as 4 months of age, but typically present between 1 – 2 years with deafness that can be confirmed using a clinical Brainstem Auditory Evoked Response (BAER) test. This type of hearing loss is distinct among other types of deafness associated with loss of pigment or other etiologies. Affected dogs do not develop other additional abnormalities.
Breed-Specific Information for the Rhodesian Ridgeback
The Mutation of the EPS8L2 gene associated with EOAD has been identified in the Rhodesian ridgeback, although its overall frequency in this breed is unknown.
Testing Tips
Genetic testing of the EPS8L2 gene in the Rhodesian Ridgeback will reliably determine whether a dog is a genetic Carrier of EOAD. EOAD is inherited in an Autosomal Recessive manner in dogs meaning that they must receive two copies of the mutated gene (one from each parent) to develop the disease. In general, carrier dogs do not have features of the disease but when bred with another carrier of the same Mutation, there is a risk of having affected pups. Each pup that is born to this pairing has a 25% chance of inheriting the disease and a 50% chance of inheriting one copy and being a carrier of the EPS8L2 gene mutation. Reliable genetic testing is important for determining breeding practices. Because symptoms may not appear until adulthood, genetic testing should be performed before breeding. In order to eliminate this mutation from breeding lines and to avoid the potential of producing affected pups, breeding of known carriers to each other is not recommended. Rhodesian ridgebacks that are not carriers of the mutation have no increased risk of having affected pups.
There may be other causes of this condition in dogs and a normal result does not exclude a different mutation in this gene or any other gene that may result in a similar genetic disease or trait.
References
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Kawakami T, Raghavan V, Ruhe AL, Jensen MK, Milano A, Nelson TC, Boyko AR. Early onset adult deafness in the Rhodesian Ridgeback dog is associated with an in-frame deletion in the EPS8L2 gene. PLoS One. 2022 Apr 6;17(4):e0264365.
[PubMed: 35385474]
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Strain GM. The Genetics of Deafness in Domestic Animals. Front Vet Sci. 2015 Sep 8;2:29. doi: 10.3389/fvets.2015.00029.
[PubMed: 26664958]
