Genetic Test
The CNGB3 (Cyclic Nucleotide-Gated Channel Beta 3) gene encodes a protein that forms the cGMP-gated ion channel in the membranes of retinal cone photoreceptor cells.
This channel is essential for converting light stimuli into electrical signals.
Mutations in CNGB3 impair normal signal transmission in cone cells, causing severe vision loss especially under bright light conditions.
The disorder typically follows an autosomal recessive inheritance pattern, with clinical signs manifesting in individuals homozygous for the mutation.
Disease Description
Day blindness (Achromatopsia) in dogs caused by CNGB3 mutations is a hereditary retinal disorder characterized by loss of cone photoreceptor function.
Affected dogs experience a marked reduction in vision under bright light, while vision in low-light conditions such as nighttime or indoors remains relatively normal or near normal.
These dogs have difficulty recognizing objects in strong daylight, impacting their daily activities.
Some individuals may also exhibit impaired color discrimination, sometimes appearing completely color blind.
Additional signs can include photophobia (light sensitivity), unstable gaze, and behavioral withdrawal.
