rs768735888

Variant names:

• chr8-86626044-AC-A
• rs768735888
• NM_019098.5:c.1516delG

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_019098.5(CNGB3):​c.1516delG​(p.Val506SerfsTer3) variant causes a frameshift change. The variant allele was found at a frequency of 0.0000031 in 1,613,808 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: CNGB3 NM_019098.5 frameshift
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 5.86

Genes affected

CNGB3 (HGNC:2153): (cyclic nucleotide gated channel subunit beta 3) This gene encodes the beta subunit of a cyclic nucleotide-gated ion channel. The encoded beta subunit appears to play a role in modulation of channel function in cone photoreceptors. This heterotetrameric channel is necessary for sensory transduction, and mutations in this gene have been associated with achromatopsia 3, progressive cone dystrophy, and juvenile macular degeneration, also known as Stargardt Disease. [provided by RefSeq, Feb 2010]

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 8-86626044-AC-A is Pathogenic according to our data. Variant chr8-86626044-AC-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 427663.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr8-86626044-AC-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CNGB3	NM_019098.5	c.1516delG	p.Val506SerfsTer3	frameshift_variant	Exon 13 of 18	ENST00000320005.6	NP_061971.3
CNGB3	XM_011517138.3	c.1102delG	p.Val368SerfsTer3	frameshift_variant	Exon 11 of 16		XP_011515440.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CNGB3	ENST00000320005.6	c.1516delG	p.Val506SerfsTer3	frameshift_variant	Exon 13 of 18	1	NM_019098.5	ENSP00000316605.5
CNGB3	ENST00000681546.1	n.1336delG		non_coding_transcript_exon_variant	Exon 8 of 13
CNGB3	ENST00000681746.1	n.1516delG		non_coding_transcript_exon_variant	Exon 13 of 19			ENSP00000505959.1

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152160 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.000207

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000120 AC: 3 AN: 250994 Hom.: 0 AF XY: 0.00000737 AC XY: 1 AN XY: 135632

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.0000981

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1461530 Hom.: 0 Cov.: 30 AF XY: 0.00000413 AC XY: 3 AN XY: 727064

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: 0.0000464

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152278 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74466

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.000207

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Achromatopsia 3 Pathogenic:2

Mar 27, 2017

Molecular Genetics Laboratory, Institute for Ophthalmic Research

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: research

- -

Jan 31, 2024

Fulgent Genetics, Fulgent Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Pathogenic:1

Oct 30, 2023

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.Val506Serfs*3) in the CNGB3 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in CNGB3 are known to be pathogenic (PMID: 28795510). This variant is present in population databases (rs768735888, gnomAD 0.01%). This premature translational stop signal has been observed in individual(s) with achromatopsia (PMID: 28795510). ClinVar contains an entry for this variant (Variation ID: 427663). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.070		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: rs768735888; hg19: chr8-87638272;