NM_001298.3:c.107_110delACTC

Variant names:

• chr2-98377690-CCACT-C
• rs749036398
• NM_001298.3:c.107_110delACTC

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PVS1 PP5_Moderate

The NM_001298.3(CNGA3):​c.107_110delACTC​(p.His36ArgfsTer136) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000192 in 1,460,654 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.000019 (0 hom.)
• Consequence: CNGA3 NM_001298.3 frameshift
• Clinical Significance: Pathogenic criteria provided, single submitter P:2
• Conservation: PhyloP100: 1.95
• 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: Pathogenic. The variant received 10 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PP5: Variant 2-98377690-CCACT-C is Pathogenic according to our data. Variant chr2-98377690-CCACT-C is described in ClinVar as Pathogenic. ClinVar VariationId is 438155.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CNGA3	NM_001298.3	c.107_110delACTC	p.His36ArgfsTer136	frameshift_variant	Exon 3 of 8	ENST00000272602.7	NP_001289.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CNGA3	ENST00000272602.7	c.107_110delACTC	p.His36ArgfsTer136	frameshift_variant	Exon 3 of 8	1	NM_001298.3	ENSP00000272602.2
CNGA3	ENST00000436404.6	c.107_110delACTC	p.His36ArgfsTer118	frameshift_variant	Exon 3 of 7	1		ENSP00000410070.2
CNGA3	ENST00000409937.1	n.95_98delACTC		non_coding_transcript_exon_variant	Exon 2 of 8	2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.0000192 AC: 28 AN: 1460654 Hom.: 0 AF XY: 0.0000165 AC XY: 12 AN XY: 726570

African (AFR) AF: 0.00 AC: 0 AN: 33444

American (AMR) AF: 0.00 AC: 0 AN: 44678

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26116

East Asian (EAS) AF: 0.00 AC: 0 AN: 39690

South Asian (SAS) AF: 0.00 AC: 0 AN: 85968

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53332

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5318

European-Non Finnish (NFE) AF: 0.0000243 AC: 27 AN: 1111794

Other (OTH) AF: 0.0000166 AC: 1 AN: 60314

GnomAD4 genome Cov.: 33

Alfa AF: 0.00 Hom.: 0

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, single submitter

Submissions by phenotype

Abnormality of the eye Pathogenic:1

Jan 01, 2015

NIHR Bioresource Rare Diseases, University of Cambridge

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: research

Undetermined rare ocular disorder with frequency of less than eight patients -

not provided Pathogenic:1

Sep 05, 2019

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.His36Argfs*136) in the CNGA3 gene. It is expected to result in an absent or disrupted protein product. This variant is not present in population databases (ExAC no frequency). This variant has been observed in individuals affected with achromatopsia and other inherited retinal disorders (PMID: 27624628, 28041643, Invitae). ClinVar contains an entry for this variant (Variation ID: 438155). Loss-of-function variants in CNGA3 are known to be pathogenic (PMID: 14757870, 24903488, 25637600). For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		2.0
Mutation Taster		=8/192	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.040		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: rs749036398; hg19: chr2-98994153;