Genetic Variant CNGB3:p.Arg478Gly (chr8-86628967-G-C) – ACMG Classification: Likely_pathogenic (8 pts)

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PM1PM2PP3_Strong

The NM_019098.5(CNGB3):c.1432C>G(p.Arg478Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,702 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R478Q) has been classified as Uncertain significance.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

CNGB3
NM_019098.5 missense

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 3.13

Publications

0 publications found

Variant links:

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]

CNGB3 Gene-Disease associations (from GenCC):

achromatopsia 3
Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P, PanelApp Australia
CNGB3-related retinopathy
Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
cone dystrophy
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
achromatopsia
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
severe early-childhood-onset retinal dystrophy
Inheritance: Unknown Classification: LIMITED Submitted by: Labcorp Genetics (formerly Invitae)

CNGB3 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 8 ACMG points.

PM1

In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 6 uncertain in NM_019098.5

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.955

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CNGB3	NM_019098.5 link	c.1432C>G	p.Arg478Gly	missense_variant	Exon 12 of 18	ENST00000320005.6	NP_061971.3
CNGB3	XM_011517138.3 link	c.1018C>G	p.Arg340Gly	missense_variant	Exon 10 of 16		XP_011515440.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein
CNGB3	ENST00000320005.6 link	c.1432C>G	p.Arg478Gly	missense_variant	Exon 12 of 18	1	NM_019098.5	ENSP00000316605.5
CNGB3	ENST00000681546.1 link	n.1252C>G		non_coding_transcript_exon_variant	Exon 7 of 13
CNGB3	ENST00000681746.1 link	n.1432C>G		non_coding_transcript_exon_variant	Exon 12 of 19			ENSP00000505959.1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461702

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

727152

show subpopulations

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

33464

American (AMR)

AF:

0.00

AC:

AN:

44708

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26124

East Asian (EAS)

AF:

0.00

AC:

AN:

39688

South Asian (SAS)

AF:

0.00

AC:

AN:

86256

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53418

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5764

European-Non Finnish (NFE)

AF:

8.99e-7

AC:

AN:

1111892

Other (OTH)

AF:

0.00

AC:

AN:

60388

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.375

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Cov.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.95

BayesDel_addAF

Pathogenic

0.52

BayesDel_noAF

Pathogenic

0.50

CADD

Uncertain

(source)

DANN

Uncertain

1.0

DEOGEN2

Uncertain

0.75

Eigen

Uncertain

0.28

Eigen_PC

Benign

0.14

FATHMM_MKL

Uncertain

0.96

LIST_S2

Uncertain

0.94

M_CAP

Pathogenic

0.38

MetaRNN

Pathogenic

0.96

MetaSVM

Pathogenic

1.1

MutationAssessor

Pathogenic

3.8

PhyloP100

3.1

PrimateAI

Uncertain

0.53

PROVEAN

Pathogenic

-7.0

REVEL

Pathogenic

0.87

Sift

Uncertain

0.0010

Sift4G

Pathogenic

0.0010

Polyphen

1.0

Vest4

0.95

MutPred

0.77

Loss of MoRF binding (P = 0.0494);

MVP

0.97

MPC

0.24

ClinPred

1.0

GERP RS

3.1

Varity_R

0.75

gMVP

0.89

Mutation Taster

=27/73

disease causing

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Computational scores

Splicing

Publications

Other links and lift over