Genetic Variant CRB2:p.Met1? (chr9-123356261-A-G) – ACMG Classification: Uncertain_significance (3 pts)

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PVS1_SupportingPM2

The NM_173689.7(CRB2):c.1A>G(p.Met1?) variant causes a start lost change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000199 in 1,508,714 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 Uncertain significance (★).

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 31)

Exomes 𝑓: 0.0000015 ( 0 hom. )

Consequence

CRB2
NM_173689.7 start_lost

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 1.88

Variant links:

Genes affected

CRB2 (HGNC:18688): (crumbs cell polarity complex component 2) This gene encodes a member of a family of proteins that are components of the Crumbs cell polarity complex. In mammals, members of this family are thought to play a role in many cellular processes in early embryonic development. A similar protein in Drosophila determines apicobasal polarity in embryonic epithelial cells. Mutations in this gene are associated with focal segmental glomerulosclerosis 9, and with ventriculomegaly with cystic kidney disease. [provided by RefSeq, Aug 2016]

CRB2 links:

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ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 3 ACMG points.

PVS1

Start lost variant, no pathogenic variants between lost start and next in-frame start position. Next in-frame start position is after 66 codons. Genomic position: 123362966. Lost 0.051 part of the original CDS.

PM2

Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CRB2	NM_173689.7 link	c.1A>G	p.Met1?	start_lost	Exon 1 of 13	ENST00000373631.8	NP_775960.4	Q5IJ48-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CRB2	ENST00000373631.8 link	c.1A>G	p.Met1?	start_lost	Exon 1 of 13	1	NM_173689.7	ENSP00000362734.3		Q5IJ48-1
CRB2	ENST00000359999.7 link	c.1A>G	p.Met1?	start_lost	Exon 1 of 10	2		ENSP00000353092.3		Q5IJ48-2

Frequencies

GnomAD3 genomes

AF:

0.00000658

AC:

AN:

151934

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000242

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD4 exome

AF:

0.00000147

AC:

AN:

1356780

Hom.:

Cov.:

AF XY:

0.00000150

AC XY:

AN XY:

668742

show subpopulations

Gnomad4 AFR exome

AF:

0.0000341

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:

9.39e-7

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.00000658

AC:

AN:

151934

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74200

show subpopulations

Gnomad4 AFR

AF:

0.0000242

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

not provided

Uncertain:1

Jul 23, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The frequency data for this variant in the population databases is considered unreliable, as metrics indicate insufficient coverage at this position in the ExAC database. This sequence change affects the initiator methionine of the CRB2 mRNA. The next in-frame methionine is located at codon 66. This variant has not been reported in the literature in individuals affected with CRB2-related conditions. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.21

BayesDel_noAF

Uncertain

0.060

CADD

Benign

DANN

Uncertain

0.98

DEOGEN2

Benign

0.019

.;T

Eigen

Benign

-0.18

Eigen_PC

Benign

-0.089

FATHMM_MKL

Benign

0.57

LIST_S2

Uncertain

0.90

D;D

M_CAP

Pathogenic

0.98

MetaRNN

Pathogenic

0.82

D;D

MetaSVM

Benign

-0.31

PROVEAN

Benign

-0.59

N;N

REVEL

Uncertain

0.58

Sift

Pathogenic

0.0

D;D

Sift4G

Pathogenic

0.0

D;D

Polyphen

0.18

B;B

Vest4

0.76

MutPred

0.72

Gain of sheet (P = 0.0221);Gain of sheet (P = 0.0221);

MVP

0.79

ClinPred

0.65

GERP RS

3.4

Varity_R

0.82

gMVP

0.65

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

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over