Early-onset adult sensorineural deafness (EOAD) described in the Rhodesian Ridgeback. Unlike congenital pigment-associated deafness, it affects dogs with full pigmentation and presents progressively and bilaterally, usually between 6 and 24 months. It is a genetic disease caused by a deletion in EPS8L2 that produces irreversible hearing loss; the DNA test identifies carriers and allows breeding to be planned. It is complementary to, not a substitute for, clinical examination and hearing assessment.

Applicable breed: Rhodesian Ridgeback. Carrier frequencies not well quantified in the literature (limited data).

- Normal hearing at birth; progressive hearing loss of early adult onset (from 4-6 months, typically 6-24 months)
- Bilateral and progressive involvement up to profound deafness
- Dogs with full pigmentation of coat, eyes and nose (not linked to pigmentation)
- Absence of other neurological or systemic signs
- Heterozygous carriers are clinically normal

Adult-onset deafness of the Rhodesian Ridgeback was recognised as a distinct entity among hereditary canine deafness, different from the congenital forms associated with pigmentation. Kawakami and colleagues (2022), by means of an association study, identified an in-frame 12 bp deletion in the EPS8L2 gene associated with early adult-onset deafness in the breed. OMIA records the entity as 'Deafness, EPS8L2-related' (OMIA:002550-9615).

- Test Rhodesian Ridgeback breeding dogs before mating.
- Do not mate two carriers: on average, 25% of the litter would be homozygous and could develop deafness.
- A carrier may be mated to a clear dog; test the offspring intended for breeding.
- A puppy with normal hearing in the first months does not rule out later development: do not use the puppy test as the sole criterion.
- Communicate the status to buyers of carrier animals intended for breeding.

Deafness is postnatal and progressive, so assessment in the puppy may be normal. Differential diagnosis with congenital pigment-associated deafness, otitis and acquired causes; confirmation combines auditory evoked potentials (BAER) with the genetic test. There is no treatment and adaptation relies on environmental management.

1. Kawakami T, Raghavan V, Ruhe AL, Jensen MK, Milano A, Nelson TC, Boyko AR. 2022. Early onset adult deafness in the Rhodesian Ridgeback dog is associated with an in-frame deletion in the EPS8L2 gene (PLoS One) (PMID 35385474).
2. OMIA:002550-9615 (Deafness, EPS8L2-related, Canis lupus familiaris).