rs104893615
Variant summary
Our verdict is Pathogenic. The variant received 11 ACMG points: 11P and 0B. PM1PP2PP5_Very_Strong
The NM_001298.3(CNGA3):c.1669G>A(p.Gly557Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000787 in 1,614,064 control chromosomes in the GnomAD database, with no homozygous occurrence. 13/22 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. G557G) has been classified as Likely benign.
Frequency
Consequence
NM_001298.3 missense
Scores
Clinical Significance
Conservation
Publications
- achromatopsia 2Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae), Illumina, PanelApp Australia
- CNGA3-related retinopathyInheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
- cone-rod dystrophyInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- achromatopsiaInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
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ACMG classification
Our verdict: Pathogenic. The variant received 11 ACMG points.
Transcripts
RefSeq
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| CNGA3 | ENST00000272602.7 | c.1669G>A | p.Gly557Arg | missense_variant | Exon 8 of 8 | 1 | NM_001298.3 | ENSP00000272602.2 | ||
| CNGA3 | ENST00000436404.6 | c.1615G>A | p.Gly539Arg | missense_variant | Exon 7 of 7 | 1 | ENSP00000410070.2 | |||
| CNGA3 | ENST00000409937.1 | n.1822G>A | non_coding_transcript_exon_variant | Exon 8 of 8 | 2 |
Frequencies
GnomAD3 genomes AF: 0.000112 AC: 17AN: 152180Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.000139 AC: 35AN: 251330 AF XY: 0.0000957 show subpopulations
GnomAD4 exome AF: 0.0000752 AC: 110AN: 1461884Hom.: 0 Cov.: 31 AF XY: 0.0000701 AC XY: 51AN XY: 727238 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.000112 AC: 17AN: 152180Hom.: 0 Cov.: 32 AF XY: 0.0000942 AC XY: 7AN XY: 74342 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
Achromatopsia 2 Pathogenic:2
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not provided Pathogenic:2
Published functional studies demonstrate a damaging effect with alteration of cGMP sensitivity, reduced calcium influx, and decreased cell surface expression compared to wild type (PMID: 18521937); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 11536077, 32531858, 31964843, 9662398, 25616768, 17693388, 18521937, 31456290, 31980526, 38219857) -
This sequence change replaces glycine, which is neutral and non-polar, with arginine, which is basic and polar, at codon 557 of the CNGA3 protein (p.Gly557Arg). This variant is present in population databases (rs104893615, gnomAD 0.3%). This missense change has been observed in individual(s) with achromatopsia (PMID: 17265047, 18521937, 25616768; internal data). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 9476). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt CNGA3 protein function with a positive predictive value of 95%. Experimental studies are conflicting or provide insufficient evidence to determine the effect of this variant on CNGA3 function (PMID: 17693388, 18521937). For these reasons, this variant has been classified as Pathogenic. -
Retinal dystrophy Pathogenic:2
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Inborn genetic diseases Pathogenic:1
The c.1669G>A (p.G557R) alteration is located in exon 8 (coding exon 7) of the CNGA3 gene. This alteration results from a G to A substitution at nucleotide position 1669, causing the glycine (G) at amino acid position 557 to be replaced by an arginine (R). Based on data from gnomAD, the A allele has an overall frequency of 0.01% (40/282722) total alleles studied. The highest observed frequency was 0.27% (28/10360) of Ashkenazi Jewish alleles. This alteration is one of the most common founder mutations in the Israeli population (Sharon, 2020). It has been reported in association with achromatopsia and other cone photoreceptor disorders in homozygotes and in heterozygotes with an additional CNGA3 alteration (Kohl, 1998; Wissinger, 2001; Wiszniewski, 2007; Reuter, 2008; Zelinger 2015; Matet, 2018). This amino acid position is highly conserved in available vertebrate species. This alteration is predicted to be deleterious by in silico analysis. Based on the available evidence, this alteration is classified as likely pathogenic. -
Achromatopsia Pathogenic:1
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not specified Uncertain:1
The Gly557Arg variant in CNGA3 has been identified in 1 compound heterozygous individual with achromatopsia (Kohl 1998). Functional studies indicate this variant may alter protein function (Reuter 2008), though the assay is not clinically validated. In summary, although these data favor pathogenicity of the Gly557Arg variant, additional studies are needed to fully assess its clinical significance. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at