rs199474697

Variant names:

• chr2-98395997-A-G
• rs199474697
• NM_001298.3:c.827A>G

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PM1 PM2 PP3_Moderate PP5_Very_Strong

The NM_001298.3(CNGA3):​c.827A>G​(p.Asn276Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,884 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: CNGA3 NM_001298.3 missense
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:2 O:1
• Conservation: PhyloP100: 8.95

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]

ACMG classification

Verdict is Pathogenic. Variant got 14 ACMG points.

• PM1: In a helix (size 8) in uniprot entity CNGA3_HUMAN there are 20 pathogenic changes around while only 0 benign (100%) in NM_001298.3
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.915
• PP5: Variant 2-98395997-A-G is Pathogenic according to our data. Variant chr2-98395997-A-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 156335.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr2-98395997-A-G is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CNGA3	NM_001298.3	c.827A>G	p.Asn276Ser	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.827A>G	p.Asn276Ser	missense_variant	Exon 8 of 8	1	NM_001298.3	ENSP00000272602.2
CNGA3	ENST00000436404.6	c.773A>G	p.Asn258Ser	missense_variant	Exon 7 of 7	1		ENSP00000410070.2
CNGA3	ENST00000409937.1	n.980A>G		non_coding_transcript_exon_variant	Exon 8 of 8	2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461884 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727242

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000232

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:2

Apr 25, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces asparagine, which is neutral and polar, with serine, which is neutral and polar, at codon 276 of the CNGA3 protein (p.Asn276Ser). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individuals with clinical features of achromatopsia (PMID: 21912902, 35456423, 35754085). ClinVar contains an entry for this variant (Variation ID: 156335). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt CNGA3 protein function with a positive predictive value of 95%. Experimental studies have shown that this missense change affects CNGA3 function (PMID: 35456423). In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -

Jun 17, 2021

Institute of Medical Genetics and Applied Genomics, University Hospital Tübingen

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Achromatopsia 2 Other:1

-

ClinVar Staff, National Center for Biotechnology Information (NCBI)

Significance: not provided

Review Status: no classification provided

Collection Method: literature only

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.18
BayesDel_addAF	Pathogenic	0.21	D
BayesDel_noAF	Uncertain	0.060
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.88	D;.;D;.
Eigen	Pathogenic	0.89
Eigen_PC	Pathogenic	0.81
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.99	D;D;.;D
M_CAP	Uncertain	0.28	D
MetaRNN	Pathogenic	0.92	D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.0	H;.;H;.
PrimateAI	Benign	0.41	T
PROVEAN	Pathogenic	-4.6	D;D;D;D
REVEL	Pathogenic	0.82
Sift	Uncertain	0.0020	D;D;D;D
Sift4G	Uncertain	0.016	D;D;D;D
Polyphen		1.0	D;.;D;.
Vest4		0.85
MutPred		0.62		.;.;.;Gain of phosphorylation at N280 (P = 0.0472);
MVP		1.0
MPC		0.37
ClinPred		1.0	D
GERP RS		5.2
Varity_R		0.87
gMVP		0.93

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

Publications

LitVar

Other links and lift over

dbSNP: rs199474697; hg19: chr2-99012460;