Deafness and Vestibular Dysfunction

Gene: PTPRQ

Transmission: Autosomal recessive

For an autosomal recessive genetic disease, an animal must have two copies of the mutation in question to be at risk of developing the disease.  Both parents of an affected animal must be carriers of at least one copy of the mutation.  Animals that have only one copy of the mutation are not at risk of developing the disease but are carrier animals that can pass the mutation on to future generations.

Mutation: Insertion, PTPRQ gene; c.9230_9231 insA, p. (N3077K fs STOP 24)

Medical system: Auditory, vestibular

Breeds: American Staffordshire Terrier/Amstaff, Doberman Pinscher, Labrador Retriever

Age of onset of symptoms: Three weeks of age and older.

Deafness with vestibular dysfunction is a recessive genetic disease that has been recognized in the Doberman Pincher breed for more than 30 years.  Recent gene association studies on one animal with unilateral deafness as well as head tilt identified a homozygous mutation within the PTPRQ gene as the potential genetic cause of the clinical signs and further survey studies confirmed this association. The PTPRQ gene codes for a protein involved in signal transduction that is important for the normal development of stereocils which are necessary for normal hearing and vestibular (balance) functions.  Symptoms such as head tilting, walking in circles and ataxia can be evident by three weeks of age in affected puppies. The severity of these symptoms varies, and the majority of affected animals can enjoy a good quality of life. At present, there is no medical treatment available. Given the recessive heredity of the disease, the mutation can be maintained within the breed by the presence of healthy but silent carrier animals.  Thus, identification of carrier animals via DNA tests will be important in efforts to eliminate the disease and the mutation from the breed.

It should be noted that the genetics of deafness in the dog is complex, and additional genes and mutations can be responsible for deafness with or without vestibular effects.

References:

OMIA link: [2196-9615]

Donner J, Freyer J, Davison S, et al. (2023) Genetic prevalence and clinical relevance of canine Mendelian disease variants in over one million dogs.  PLoS Genet. 19(2):e1010651. [pubmed/36848397]

Webb AA, Ruhe AL, Neff MW. (2019) A missense mutation in MYO7A is associated with bilateral deafness and vestibular dysfunction in the Doberman pinscher breed.  Can J Vet Res 83(2):142-148.  [pm/31097876]

Guevar J, Olby NJ, Meurs KM, et al. (2018) Deafness and vestibular dysfunction in a Doberman Pinscher puppy associated with a mutation in the PTPRQ gene. J Vet Intern Med 32:665-669. [pubmed/29460419]

Contributed by: Michaelle Jean and Leah Lagueux, Class of 2028, Faculty of Veterinary Medicine, University of Montreal. (Translation DWS).