PDE6C (phosphodiesterase 6C) is a cone-specific cGMP phosphodiesterase that plays an essential role in cone phototransduction by rapidly decreasing intracellular cGMP levels in response to light stimulation 1. This enzyme is part of the cone phototransduction cascade and works in coordination with other cGMP metabolism regulators; its stability and function are interdependent with other phototransduction proteins like guanylate cyclase 2. Pathogenic variants in PDE6C cause achromatopsia and cone dystrophy, disorders affecting color vision and cone photoreceptor function 34. PDE6C mutations account for a portion of achromatopsia cases, though CNGA3 and CNGB3 variants are more prevalent 1. PDE6C-related retinopathy presents as a severe cone dysfunction syndrome characterized by early-onset nystagmus, poor visual acuity, complete color vision loss, photophobia, and progressive maculopathy with outer retinal atrophy 56. Some patients develop cone-rod dystrophy with additional scotopic dysfunction and visual field constriction 6. High myopia frequently accompanies PDE6C-related disease 5. Clinically, affected individuals typically present at birth or early infancy with poor vision and color blindness 1. Currently, no FDA-approved treatments exist, though gene therapy approaches show preclinical promise with clinical trials underway 1.