Test Detail

Molecular test for two forms of hereditary non-syndromic sensorineural deafness in dogs. In the Dobermann it is associated with a variant in the PTPRQ gene (congenital deafness with vestibular dysfunction); in the Beauceron it is caused by a variant in the CDH23 gene (bilateral deafness in puppies, not linked to coat colour). Both are inherited in an autosomal recessive manner. The test reports clear/carrier/affected status for the variant corresponding to each breed.

Breeds with a documented variant: Dobermann (PTPRQ) and Beauceron (CDH23). Carrier frequencies: ~1.5% in 202 unaffected Dobermanns (PTPRQ) and 3.3% in 90 control Beaucerons (CDH23). There are no published data justifying the inclusion of other breeds.

- Congenital or early-onset hearing loss
- In the Dobermann, deafness accompanied by vestibular dysfunction (loss of balance, nystagmus)
- Lack of response to noises and calls
- Lord sign (head movement towards the sound source)
- Normal otoscopy, with no abnormality of the ear canal/tympanum

The PTPRQ form was identified by whole-genome sequencing in a Dobermann puppy with deafness and vestibular dysfunction (Guevar et al., 2018); allele prevalence was 1.5% in 202 unaffected Dobermanns and the suggested inheritance was autosomal recessive. The CDH23 form was described in Beaucerons with bilateral deafness not linked to coat colour (Abitbol et al., 2023), with a carrier frequency of 3.3% in 90 control Beaucerons and autosomal recessive inheritance. The variant of one gene should not be attributed to the breed of the other.

- Genotype breeding dogs before mating
- Do not mate carrier×carrier (25% risk of affected homozygotes); carrier×clear produces 0% affected and 50% carriers
- An affected animal must not be bred; a carrier may be mated to a clear dog without producing affected offspring
- After a confirmed clinical case, do not repeat the parental mating and inform the buyer of the status

Confirmation by BAER/BAEP (auditory evoked potentials) and prior otoscopy to rule out external/media otitis. Differentiate from pigment-associated deafness (spotted/merle breeds) and from acquired deafness (chronic otitis, toxins, senile). The molecular test confirms the genetic status, but the clinical phenotype must be verified by audiometry, since forms of different origin may occur in the same breed. The PTPRQ variant is specific to the Dobermann and the CDH23 variant to the Beauceron.

1. Guevar J et al. (2018) Deafness and vestibular dysfunction in a Doberman Pinscher puppy associated with a mutation in the PTPRQ gene. J Vet Intern Med. PMID: 29460419
2. Abitbol M et al. (2023) A CDH23 missense variant in Beauceron dogs with non-syndromic deafness. Anim Genet. PMID: 36308003
3. OMIA:002196-9615 Deafness, unilateral and vestibular dysfunction, PTPRQ-related. https://omia.org/OMIA002196/9615/
4. OMIA:002584-9615 Deafness, CDH23-related. https://omia.org/OMIA002584/9615/