Genetic Test
The CNGB3 (Cyclic Nucleotide-Gated Channel Subunit Beta 3) gene encodes a protein that is a component of cyclic nucleotide-gated (CNG) ion channels. These channels play a critical role in the function of cone photoreceptors, which are responsible for color vision and visual acuity in bright light conditions.
Mutations in the CNGB3 gene have been associated with various retinal disorders, including achromatopsia (complete color blindness), cone dystrophy, and macular degeneration.
This genetic test specifically targets a known mutation in the CNGB3 gene that is associated with cone degeneration, a condition affecting cone cells in the retina.
Cone degeneration can lead to progressive loss of daytime vision, decreased visual acuity, and impaired color perception. In affected animals, symptoms typically begin with photophobia (sensitivity to light) and visual difficulties in well-lit environments. As the condition progresses, the cone cells deteriorate, while rod cells may remain functional, allowing for preserved night vision in early stages. However, eventual widespread retinal degeneration may occur in some cases.
Disease Description
Cone degeneration is a type of inherited retinal disorder caused by dysfunction of cone photoreceptor cells in the retina, which are responsible for vision in bright light and color perception.
In dogs, cone cells help maintain clear vision during the daytime. However, when cone degeneration occurs, affected animals experience a progressive loss of cone cell function, leading to an impaired ability to see in bright light. This results in photophobia (light sensitivity), eye discomfort, and even temporary blindness in well-lit environments. As a result, dogs may become hesitant or fearful when entering brightly lit areas.
Despite these difficulties during the day, their vision at night often remains relatively unaffected because rod photoreceptors—which are responsible for vision in low-light conditions—continue to function normally in the early stages. This contrast between day and night vision is a hallmark of cone degeneration.
