Because loss-of-function of CNGB3 causes achromatopsia and there was no disease phenotype in both CNGB3+/+ and CNGB3+/− mice,26 we inferred that the decrease in CNGB3 resulted from successful biallelic deletion of CNGB3 in two of three cones in cone_6. Here, CNGB3 is linked to achromatopsia.