rs398122736

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 0P and 2B. BP4_Moderate

The NM_000059.4(BRCA2):c.1966A>G(p.Thr656Ala) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00002 in 1,603,674 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 12/18 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. T656I) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000021 ( 0 hom. )

Consequence

BRCA2
NM_000059.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:7B:1

Conservation

PhyloP100: -0.729

Variant links:

Genes affected

BRCA2 (HGNC:1101): (BRCA2 DNA repair associated) Inherited mutations in BRCA1 and this gene, BRCA2, confer increased lifetime risk of developing breast or ovarian cancer. Both BRCA1 and BRCA2 are involved in maintenance of genome stability, specifically the homologous recombination pathway for double-strand DNA repair. The largest exon in both genes is exon 11, which harbors the most important and frequent mutations in breast cancer patients. The BRCA2 gene was found on chromosome 13q12.3 in human. The BRCA2 protein contains several copies of a 70 aa motif called the BRC motif, and these motifs mediate binding to the RAD51 recombinase which functions in DNA repair. BRCA2 is considered a tumor suppressor gene, as tumors with BRCA2 mutations generally exhibit loss of heterozygosity (LOH) of the wild-type allele. [provided by RefSeq, May 2020]

BRCA2 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -2 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.094239414).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
BRCA2	NM_000059.4 linkuse as main transcript	c.1966A>G	p.Thr656Ala	missense_variant	11/27	ENST00000380152.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
BRCA2	ENST00000380152.8 linkuse as main transcript	c.1966A>G	p.Thr656Ala	missense_variant	11/27	5	NM_000059.4	A2

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152264

Hom.:

Cov.:

show subpopulations

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:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000294

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.00000822

AC:

AN:

243408

Hom.:

AF XY:

0.0000152

AC XY:

AN XY:

131432

show subpopulations

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:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000899

Gnomad OTH exome

AF:

0.000171

GnomAD4 exome

AF:

0.0000207

AC:

AN:

1451410

Hom.:

Cov.:

AF XY:

0.0000153

AC XY:

AN XY:

721184

show subpopulations

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:

0.0000262

Gnomad4 OTH exome

AF:

0.0000167

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152264

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74388

show subpopulations

Gnomad4 AFR

AF:

0.00

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:

0.0000294

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000625

Hom.:

Bravo

AF:

0.0000151

ExAC

AF:

0.00000824

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:7Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Hereditary cancer-predisposing syndrome

Uncertain:2Benign:1

Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	May 24, 2022	The p.T656A variant (also known as c.1966A>G), located in coding exon 10 of the BRCA2 gene, results from an A to G substitution at nucleotide position 1966. The threonine at codon 656 is replaced by alanine, an amino acid with similar properties. This amino acid position is not well conserved in available vertebrate species. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -
Likely benign, criteria provided, single submitter	curation	University of Washington Department of Laboratory Medicine, University of Washington	Mar 23, 2023	Missense variant in a coldspot region where missense variants are very unlikely to be pathogenic (PMID:31911673). -
Uncertain significance, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Feb 28, 2023	This missense variant replaces threonine with alanine at codon 656 of the BRCA2 protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in an individual with a personal or family history of breast and/or ovarian cancer (PMID: 21120943). In a large breast cancer case-control meta analysis conducted by the BRIDGES consortium, this variant was reported in 2/60466 cases and 1/53461 controls (PMID: 33471991; Leiden Open Variation Database DB-ID BRCA2_002974). This variant has been identified in 2/243408 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -

not specified

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Genetic Services Laboratory, University of Chicago	Nov 09, 2018	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Sep 18, 2023	Variant summary: BRCA2 c.1966A>G (p.Thr656Ala) results in a non-conservative amino acid change in the encoded protein sequence. Four of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 8.2e-06 in 243408 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.1966A>G has been reported in the literature in individuals affected with breast- and/or ovarian cancer (e.g. Caux-Moncoutier_2011, Dorling_2021), but was also found in controls (Dorling_2021). These report(s) do not provide unequivocal conclusions about association of the variant with Hereditary Breast And Ovarian Cancer Syndrome. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publications have been ascertained in the context of this evaluation (PMID: 21120943, 25348012, 33471991). Six submitters have cited clinical-significance assessments for this variant to ClinVar after 2014. Based on the evidence outlined above, the variant was classified as uncertain significance. -

Breast-ovarian cancer, familial, susceptibility to, 2

Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

Sharing Clinical Reports Project (SCRP)

Apr 10, 2013

- -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Aug 14, 2020

Not observed at a significant frequency in large population cohorts (Lek 2016); In silico analysis supports that this missense variant does not alter protein structure/function; Observed in at least one individual undergoing BRCA1/2 testing (Caux-Moncoutier 2011); Also known as 2194A>G; This variant is associated with the following publications: (PMID: 21120943) -

Hereditary breast ovarian cancer syndrome

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Nov 08, 2023

This sequence change replaces threonine, which is neutral and polar, with alanine, which is neutral and non-polar, at codon 656 of the BRCA2 protein (p.Thr656Ala). This variant is present in population databases (rs398122736, gnomAD 0.0009%). This missense change has been observed in individual(s) with hereditary breast and ovarian cancer (PMID: 21120943). ClinVar contains an entry for this variant (Variation ID: 91765). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt BRCA2 protein function with a negative predictive value of 95%. 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. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.066

BayesDel_addAF

Benign

-0.27

BayesDel_noAF

Benign

-0.62

Cadd

Benign

0.41

Dann

Uncertain

0.99

Eigen

Benign

-1.3

Eigen_PC

Benign

-1.3

FATHMM_MKL

Benign

0.036

M_CAP

Benign

0.019

MetaRNN

Benign

0.094

T;T

MetaSVM

Benign

-0.94

MutationTaster

Benign

1.0

N;N

PrimateAI

Benign

0.21

PROVEAN

Benign

-0.78

N;N

REVEL

Benign

0.031

Sift

Benign

0.16

T;T

Sift4G

Benign

0.14

T;T

Vest4

0.12

MVP

0.68

MPC

0.021

ClinPred

0.015

GERP RS

-6.0

gMVP

0.094

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