Retinal atrophy, Cone-rod dystrophy (NPHP4 related)

 

Gene: NPHP4

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: Deletion, NPHP4 gene; del.180bp, exon4-intron4-5

Medical system: Ocular

Breed: Dachshund Miniature Longhair/Shorthair, Dachshund Miniature Wirehair, Dachshund Standard Longhair/Shorthair, Dachshund Standard Wirehair

Age of onset of symptoms: Anomalies at the veterinary ophthalmic examination between 10 months and 3 years. Complete blindness reached on average around the age of 6 years.

Progressive retinal atrophy (PRA) refers to a group of diseases affecting the retina including degeneration of cone and rod receptor cells. The PRA-CRD-SWD of Dachshunds is a retinal disease that appears in adulthood.  Since cone receptors (color vision) are the first cells to be affected, the first symptoms to appear are losing day vision. The disease progresses gradually and eventually the rod receptors (dim light vision) are affected, resulting in a loss of night vision. Changes in the retina can be observed during an ophthalmic examination between 10 months and 3 years.  Affected animals usually become blind by the age of six years.

 

References :

OMIA link: [1455-9615]

Genetics Committee of the American College of Veterinary Ophthalmologists. (2021) The Blue Book: Ocular disorders presumed to be inherited in purebred dogs. 13th Edition.  [https://ofa.org/wp-content/uploads/2022/10/ACVO-Blue-Book-2021.pdf]

Palanova A. (2016) The genetics of inherited retinal disorders in dogs: implications for diagnosis and management.  Vet Med (Auckl). 7:41-51. [pubmed/30050836]

Downs LM, Hitti R, Pregnolato S, Mellersh CS. (2014) Genetic screening for PRA-associated mutations in multiple dog breeds shows that PRA is heterogeneous within and between breeds.  Vet Ophthalmol. 17(2):126-30.  [pubmed/29255994]

Palánová A, Schröffelová D, Přibáňová M, et al. (2014) Analysis of a deletion in the nephronophthisis 4 gene in different dog breeds. Vet Ophthalmol. 17(1):76-8. [pubmed/23998563]

Wiik AC, Thoresen SI, Wade C, et al. (2009) A population study of a mutation allele associated with cone-rod dystrophy in the standard wire-haired dachshund. Anim Genet. 40(4):572-4. [pubmed/19392817]

Wiik AC, Wade C, Biagi T, et al. (2008) A deletion in nephronophthisis 4 (NPHP4) is associated with recessive code-rod dystrophy in standard wire-haired daschund. Genome Research 18: 1415-1421. [pubmed/18687878]