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Early Onset Adult Deafness (EOAD) - Rhodesian Ridgeback Type
| Acronym: | EOAD |
| Gene: | EPS8L2 |
| Mutation: | g.25752663_25752674del |
| Inheritance: | Autosomal Recessive |
| Sample type: | CHS (Cheek Swab), WBE (Whole Blood EDTA) |
Genetics and characteristics
Early Onset Adult Deafness (EOAD) is a genetic congenital syndrome of hearing loss and inner ear dysfunction in humans and animals, including dogs. Deafness is observed in various dog breeds with different clinical characteristics and different genetic architecture. This specific type observed as early as four months of age but more commonly observed within 1–2 years after birth, is specific for Rhodesian Ridgeback dogs. Affected Rhodesian Ridgebacks suffer from progressive postnatal deafness where they completely lose their hearing ability within 1–2 years after birth. However, affected dogs do not show any noticeable association with pigmentation patterns as is often the case with other hearing loss diseases. The cause of this type of early-onset deafness is a deletion in the EPS8L2 gene that encodes a protein expressed in cochlear hair cells. Gene product of the EPS8L2 gene plays an important role in the maintenance and integrity of the inner ear hair cells in humans and other mammals.
This early-onset hearing loss in Rhodesian Ridgeback dogs is inherited as an autosomal recessive trait requiring two copies of the mutated gene for the disease to develop. Dogs with only one copy of the mutated gene will not develop the disease but may act as carriers and pass the mutation to their offspring. Early detection by genetic testing can identify dogs with the specific mutation and help breeders in selecting future mating pairs.
Results Reported As
Test Result |
Interpretation of test result |
CLEAR |
Tested mutation was not detected in animal with „clear“ result. Animal tested as clear has wild-type allele in homozygous state (i.e. two pairs of healthy alleles). It will not develop disease caused by tested mutation.* It will pass only wild-type allele to its offspring. |
CARRIER |
Tested mutation was detected in animal with „carrier“ result. Animal tested as carrier has one wild-type and one mutation allele, it is in heterozygous state. It will not develop disease caused by tested mutation.* It can pass wild-type or mutation allele to its offspring. |
AFFECTED |
Tested mutation was detected in animal with „affected“ result. Animal tested as affected has two copies of mutation alleles affecting the gene. It is likely the animal will experience a genetic disorder due to this mutation.** It will pass only mutation allele to its offspring. |
*Test excludes only tested mutation but not possible unknown mutations or factors that can lead to similar condition/symptoms.
** Potential unknown mutations or multiple other factors can possibly affect the likelihood of experiencing a genetic disorder.
References:
Kawakami, T., Raghavan, V., Ruhe, A. L., Jensen, M. K., Milano, A., Nelson, T. C., Boyko, A. R. (2022). Early onset adult deafness in the Rhodesian Ridgeback dog is associated with an in-frame deletion in the EPS8L2 gene. PloS one, 17(4), e0264365. https://doi.org/10.1371/journal.pone.0264365
Strain G. M. (2015). The Genetics of Deafness in Domestic Animals. Frontiers in veterinary science, 2, 29. https://doi.org/10.3389/fvets.2015.00029