CNGA3 and achromatopsia 2: Variants in the CNGA3 gene, located on chromosome 2q11, which encodes the alpha subunit of the cone photoreceptor cGMP-gated cation channel, are the cause of achromatopsia 2 (ACHM2; OMIM 216900) (Dubis et al., 2014; Fischer et al., 2020).