Disease overview

PRA-2 causes the breakdown of the retina, which is a part of the eye essential for vision. This progressive, non-painful disease affects both types of photoreceptors: rods and cones. Rod cells are responsible for vision in low light conditions and for detecting and following movement, while cone cells detect color and adjust brightness, but do not work as well in low light. PRA-2 typically begins with symptoms of night blindness, and eventually leads to daytime vision loss.

Gene name

TTC8

Inheritance

Autosomal recessive

Signs and symptoms

PRA-2 is a slowly progressive disease with slow vision loss in both eyes. This provides more opportunities for helping an affected dog adapt to its changing visual environment. This disease has a late-onset of around 4 years of age. Signs typically begin with night blindness, which progresses to daytime vision loss.

How is it diagnosed

Thorough examination of the eyes and clinical signs. A veterinary ophthalmologic exam can determine if there are changes in the eye that have or will lead to vision loss. Genetic testing is necessary to determine if there is an underlying genetic cause, which can assist veterinarians with diagnosis and help breeders identify affected and carrier dogs.

Breeds at higher risk

Citations

Downs LM, Wallin-Håkansson B, Bergström T, Mellersh CS. A novel mutation in TTC8 is associated with progressive retinal atrophy in the golden retriever. Canine Genet Epidemiol. 2014 Apr 16;1:4. doi: 10.1186/2052-6687-1-4. PMID: 26401321; PMCID: PMC4574394.

Disclaimer

Disease diagnosis and treatment should always be performed by a veterinarian. The following information is for educational purposes only.