Humans with CNGB1-related RP (12, 13, 16, 23), mice (Cngb1-X26) (27), and Cngb1–/– dogs with mutations that spare expression of the alternatively expressed GARP subunits share a similar phenotype characterized by a lack of rod-mediated retinal function from an early age, followed by a slowly progressive age-related loss of cone function and, in humans, constriction of visual fields. This evidence concerns the gene CNGB1 and retinitis pigmentosa 1.