{{Rsnum
|rsid=121918344
|Chromosome=8
|Orientation=minus
|geno1=(C;C)
|geno2=(C;T)
|geno3=(T;T)
|Gene=CNGB3
|position=86632768
|Assembly=GRCh38
|GenomeBuild=38.1
|dbSNPBuild=141
|Gene_s=CNGB3
}}[[rs121918344]], also known as S435F or SER322PHE, is a SNP in the cyclic nucleotide-gated channel beta-3 [[CNGB3]] gene.

Originally observed in Pingelapese islanders, a condition involving total colorblindness, photophobia, nystagmus, 20/200 visual acuity, yet a normal-appearing retina, was eventually found by sequence analysis to be due to a C-to-T transition causing a serine-to-phenylalanine substitution at amino acid 435 of this ([[CNGB3]]) gene.{{PMID|10888875}}

{{omim
|id=605080
|rsnum=121918344
|variant=0001
}}{{ClinVar
|rsid=121918344
|Reversed=1
|FwdREF=C
|FwdALT=T
|REF=G
|ALT=A
|RSPOS=87644996
|CHROM=8
|dbSNPBuildID=133
|SSR=0
|SAO=1
|VP=0x050060000000000002110100
|GENEINFO=CNGB3:54714
|GENE_NAME=CNGB3
|GENE_ID=54714
|WGT=0
|VC=SNV
|CLNALLE=1
|CLNHGVS=NC_000008.10:g.87644996G>A
|CLNSRC=GeneReviews; OMIM Allelic Variant
|CLNORIGIN=1
|CLNSRCID=NBK1418; 605080.0001
|CLNSIG=5
|CLNCUI=C1849792
|CLNDBN=Achromatopsia 3
|Disease=Achromatopsia 3
|CLNACC=RCV000005532.2
|Tags=RV;PM;OTHERKG;LSD;OM
|CLNDSDB=GeneReviews:MedGen:OMIM:Orphanet
|CLNDSDBID=NBK1418:C1849792:262300:49382
}}