Early Adult Onset Deafness (EAOD)
Inheritance: Autosomal recessive with incomplete penetrance
Symptoms: Progressive hearing loss usually observed between the age of 5-7 but may be noticed at 18 - 24 mo and as late as 8 -10 yo.
Description:
US working border collie owners identified the problem with adult onset hearing loss in the prime of a working dog's life around 20 years ago. Research has been undertaken for 15 + years with initial funding from the American Border Collie Association. Because it appears to affect a dog unilaterally then bilaterally, it is often not identified until the dog is nearly completely deaf. Research is ongoing to identify the causal gene mutation. BAER testing is needed to check hearing loss.
EAOD is found in border collies worldwide from working and ANKC show lines. The large approx. 1000 dog Finnish study at the University of Helsinki used BCs from around the world including those of ANKC origin.
The test is a linkage marker test based on 4 markers developed by the Lohi lab at the University of Helsinki (offered by MyDogDNA/Optimal Selection, although Orivet uses a single marker from an earlier paper). The 4 marker test became available in August 2019.