Based on this cfh-1 mutant phenotype and the central role of CNG channels in the visual cycle in the vertebrate retina, the distribution of CNGA1 and CNGB1 were examined in post-mortem tissue from individuals at low-risk (CFH Y402) and high-risk (CFH Y402H) for AMD (30). Here, CNGA1 is linked to age-related macular degeneration.