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.

Gene name

CCDC66

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 2-5 years of age. Signs typically start with night blindness and progress 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

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Citations

Dekomien G, Vollrath C, Petrasch-Parwez E, Boevé MH, Akkad DA, Gerding WM, Epplen JT. Progressive retinal atrophy in Schapendoes dogs: mutation of the newly identified CCDC66 gene. Neurogenetics. 2010 May;11(2):163-74. doi: 10.1007/s10048-009-0223-z. Epub 2009 Sep 24. PMID: 19777273.

Murgiano L, Becker D, Spector C, Carlin K, Santana E, Niggel JK, Jagannathan V, Leeb T, Pearce-Kelling S, Aguirre GD, Miyadera K. CCDC66 frameshift variant associated with a new form of early-onset progressive retinal atrophy in Portuguese Water Dogs. Sci Rep. 2020 Dec 3;10(1):21162. doi: 10.1038/s41598-020-77980-5. PMID: 33273526; PMCID: PMC7712861.

Disclaimer

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