Disease overview

Rod-Cone Dysplasia 3 (RCD3) is a form of early-onset progressive retinal atrophy. This is a non-painful eye disorder 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. RCD3 causes retinal degeneration as early as 4 weeks of age.

Gene name

PDE6A

Inheritance

Autosomal recessive

Signs and symptoms

Progressive retinal atrophy (PRA) is typically characterized by a loss of vision over time, which can allow for a dog to adapt more easily. Signs of change in the tapetum, which is the reflective surface of the eye, may be evident. These changes first cause night blindness, progressing to vision loss during the day and then often to complete blindness for most dogs. Changes in behavior such as reluctance to go down the stairs or into a dark room, and bumping into door frames and furniture may be signs that a dog is experiencing vision loss. This form of PRA can lead to complete blindness, typically by 1 year of age.

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

Petersen-Jones SM, Entz DD, Sargan DR. cGMP phosphodiesterase-alpha mutation causes progressive retinal atrophy in the Cardigan Welsh corgi dog. Invest Ophthalmol Vis Sci. 1999 Jul;40(8):1637-44. PMID: 10393029.

Disclaimer

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