Disease overview

Progressive Retinal Atrophy (PRA) causes breakdown of the retina, which is a part of the eye essential for vision. This is a progressive, non-painful disease that 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. This type of PRA leads to earlier loss of rod cells, which leads to night blindness prior to any onset of day blindness.

Gene name

CNGA1

Inheritance

Autosomal recessive

Signs and symptoms

PRA is a slowly progressive disease that causes 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 5 years of age. Signs typically start 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

Wiik AC, Ropstad EO, Ekesten B, Karlstam L, Wade CM, Lingaas F. Progressive retinal atrophy in Shetland sheepdog is associated with a mutation in the CNGA1 gene. Anim Genet. 2015 Oct;46(5):515-21. doi: 10.1111/age.12323. Epub 2015 Jul 22. PMID: 26202106.

Disclaimer

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