rs878853394

Positions:

• chr16-57964158-G-A

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PVS1 PM2 PP5

The NM_001297.5(CNGB1):​c.262C>T​(p.Gln88*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,862 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 (no stars). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: CNGB1 NM_001297.5 stop_gained
• Clinical Significance: Pathogenic/Likely pathogenic no assertion criteria provided P:3
• Conservation: PhyloP100: 2.25

Genes affected

CNGB1 (HGNC:2151): (cyclic nucleotide gated channel subunit beta 1) In humans, the rod photoreceptor cGMP-gated cation channel helps regulate ion flow into the rod photoreceptor outer segment in response to light-induced alteration of the levels of intracellular cGMP. This channel consists of two subunits, alpha and beta, with the protein encoded by this gene representing the beta subunit. Defects in this gene are a cause of cause of retinitis pigmentosa type 45. Three transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Oct 2013]

CNGB1 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 11 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 16-57964158-G-A is Pathogenic according to our data. Variant chr16-57964158-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 236512.Status of the report is no_assertion_criteria_provided, 0 stars. Variant chr16-57964158-G-A is described in Lovd as [Likely_pathogenic]. Variant chr16-57964158-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CNGB1	NM_001297.5	c.262C>T	p.Gln88*	stop_gained	4/33	ENST00000251102.13	NP_001288.3
CNGB1	NM_001286130.2	c.262C>T	p.Gln88*	stop_gained	4/33		NP_001273059.1
CNGB1	NM_001135639.2	c.262C>T	p.Gln88*	stop_gained	4/13		NP_001129111.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CNGB1	ENST00000251102.13	c.262C>T	p.Gln88*	stop_gained	4/33	1	NM_001297.5	ENSP00000251102.8

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461862 Hom.: 0 Cov.: 31 AF XY: 0.00000275 AC XY: 2 AN XY: 727234

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: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000270

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:3

Revision: no assertion criteria provided

Submissions by phenotype

CNGB1-related disorder Pathogenic:1

Pathogenic, no assertion criteria provided

clinical testing

PreventionGenetics, part of Exact Sciences

May 06, 2024

The CNGB1 c.262C>T variant is predicted to result in premature protein termination (p.Gln88*). This variant has been reported along with a second CNGB1 variant in individuals with retinaly dystrophy (Table S5, Ellingford et al. 2016. PubMed ID: 27208204; Hull et al. 2017. PubMed ID: 28056120). This variant has not been reported in a large population database, indicating this variant is rare. Nonsense variants in CNGB1 are expected to be pathogenic. Given the evidence, we interpret this variant as pathogenic. -

Retinal dystrophy Pathogenic:1

Likely pathogenic, no assertion criteria provided

clinical testing

Centre for Genomic Medicine, Manchester, Central Manchester University Hospitals

-

- -

Retinitis pigmentosa Pathogenic:1

Likely pathogenic, no assertion criteria provided

research

NIHR Bioresource Rare Diseases, University of Cambridge

Jan 01, 2015

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Uncertain	0.050
CADD	Pathogenic	33
DANN	Uncertain	1.0
Eigen	Uncertain	0.34
Eigen_PC	Benign	-0.024
FATHMM_MKL	Benign	0.19	N
Vest4		0.81
GERP RS		2.7

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.12		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: rs878853394; hg19: chr16-57998062;