2-98396627-G-C

Variant names:

• chr2-98396627-G-C
• rs786205531
• NM_001298.3:c.1457G>C

Variant summary

Our verdict is Likely pathogenic. The variant received 9 ACMG points: 9P and 0B. PM1 PM2 PM5 PP2 PP3_Moderate

The NM_001298.3(CNGA3):​c.1457G>C​(p.Cys486Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. C486R) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: CNGA3 NM_001298.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.60
• Publications: 1 publications found

Genes affected

CNGA3 (HGNC:2150): (cyclic nucleotide gated channel subunit alpha 3) This gene encodes a member of the cyclic nucleotide-gated cation channel protein family which is required for normal vision and olfactory signal transduction. Mutations in this gene are associated with achromatopsia (rod monochromacy) and color blindness. Two alternatively spliced transcripts encoding different isoforms have been described. [provided by RefSeq, Jul 2008]

CNGA3 Gene-Disease associations (from GenCC):

• achromatopsia 2

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae), Illumina, PanelApp Australia
• CNGA3-related retinopathy

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• cone-rod dystrophy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• achromatopsia

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Likely_pathogenic. The variant received 9 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 6 uncertain in NM_001298.3
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr2-98396626-T-C is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 3248784.Status of the report is criteria_provided_single_submitter, 1 stars.
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 105 curated pathogenic missense variants (we use a threshold of 10). The gene has 14 curated benign missense variants. Trascript score misZ: 0.49806 (below the threshold of 3.09). GenCC associations: The gene is linked to achromatopsia 2, CNGA3-related retinopathy, cone-rod dystrophy, achromatopsia.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.929

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CNGA3	NM_001298.3	c.1457G>C	p.Cys486Ser	missense_variant	Exon 8 of 8	ENST00000272602.7	NP_001289.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CNGA3	ENST00000272602.7	c.1457G>C	p.Cys486Ser	missense_variant	Exon 8 of 8	1	NM_001298.3	ENSP00000272602.2
CNGA3	ENST00000436404.6	c.1403G>C	p.Cys468Ser	missense_variant	Exon 7 of 7	1		ENSP00000410070.2
CNGA3	ENST00000409937.1	n.1610G>C		non_coding_transcript_exon_variant	Exon 8 of 8	2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Jul 31, 2025

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: CNGA3 c.1457G>C (p.Cys486Ser) results in a non-conservative amino acid change in the encoded protein sequence. Algorithms developed to predict the effect of missense changes on protein structure and function all suggest that this variant is likely to be disruptive. The variant was absent in 250798 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. To our knowledge, no occurrence of c.1457G>C in individuals affected with Achromatopsia 2 and no experimental evidence demonstrating its impact on protein function have been reported. No submitters have cited clinical-significance assessments for this variant to ClinVar. Based on the evidence outlined above, the variant was classified as uncertain significance.

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.65
BayesDel_addAF	Pathogenic	0.51	D
BayesDel_noAF	Pathogenic	0.49
CADD	Pathogenic	28
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.67	D;.;D;.
Eigen	Pathogenic	0.93
Eigen_PC	Pathogenic	0.86
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.99	D;D;.;D
M_CAP	Pathogenic	0.33	D
MetaRNN	Pathogenic	0.93	D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.2	M;.;M;.
PhyloP100		9.6
PrimateAI	Uncertain	0.79	T
PROVEAN	Pathogenic	-9.3	D;D;D;D
REVEL	Pathogenic	0.94
Sift	Uncertain	0.0010	D;D;D;D
Sift4G	Uncertain	0.0080	D;D;D;D
Vest4		0.87
ClinPred		1.0	D
GERP RS		4.9
Varity_R		0.91
gMVP		0.80
Mutation Taster		=4/96	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs786205531; hg19: chr2-99013090;