Deafness in Doberman Pinscher

Hereditary deafness in Doberman pinschers can be bilateral or unilateral and is caused by different mutations in different genes. Both variants are accompanied by dysfunction of the vestibular system.

Congenital bilateral deafness with concurrent dysfunction of the vestibular system was first described in Dobermans in the 1980s. Clinical signs are already evident in puppies lacking the vestibulo-ocular reflex. Variable loss of the righting reflex may be evident early, though this tends to improve with age. Affected dogs suffer from complete sensorineural hearing loss and vestibular dysfunction, which is manifested by a head/neck excursion, frequent falls, or an unnatural head tilt backwards.

Unilateral deafness begins to manifest in puppies by 3 weeks of age and is also accompanied by signs of vestibular dysfunction – head tilt, circling during movement and ataxia.

While the bilateral variant of this disease is caused by the missense mutation c.3719G>A in the MYO7A gene, the unilateral variant is due to the mutation c.9230_9231insA in the PTPRQ gene.

Both mutations have autosomal recessive inheritance. This means that only individuals who inherit the mutated gene from both parents will develop the disease. Carriers of the mutated gene are clinically healthy but pass the mutation on to their offspring. In the case of a mating between two heterozygous individuals, theoretically 25% of the offspring will be completely healthy, 50% of the offspring will be carriers and 25% of the offspring will inherit the mutated gene from both parents and will therefore be affected by the disease.

The genetic test can clearly reveal the genotype of the animal and is a useful tool for breeders to avoid unintentional breeding of affected puppies.

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References:

Webb, A.A., Ruhe, A.L., Neff, M.W., Webb, A.A., Ruhe, A.L., Neff, M.W. : A missense mutation in MYO7A is associated with bilateral deafness and vestibular dysfunction in the Doberman pinscher breed. Can J Vet Res 83:142-148, 2019. Pubmed reference: 31097876

Guevar, J., Olby, N.J., Meurs, K.M., Yost, O., Friedenberg, S.G. : Deafness and vestibular dysfunction in a Doberman Pinscher puppy associated with a mutation in the PTPRQ gene. J Vet Intern Med 32:665-669, 2018. Pubmed reference: 29460419