13-32363525-A-G

Position:

• chr13-32363525-A-G

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM1 PM2 PM5

The NM_000059.4(BRCA2):​c.8323A>G​(p.Met2775Val) variant causes a missense change. The variant allele was found at a frequency of 0.000000685 in 1,460,314 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. M2775R) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: BRCA2 NM_000059.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:4
• Conservation: PhyloP100: 4.13

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]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 4 benign, 15 uncertain in NM_000059.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr13-32363525-ATG-AA is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
BRCA2	NM_000059.4	c.8323A>G	p.Met2775Val	missense_variant	18/27	ENST00000380152.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
BRCA2	ENST00000380152.8	c.8323A>G	p.Met2775Val	missense_variant	18/27	5	NM_000059.4	A2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000404 AC: 1 AN: 247808 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 134158

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: 0.00000905

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1460314 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 726548

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: 9.00e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Breast-ovarian cancer, familial, susceptibility to, 2 Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

Department of Medical Genetics, University Hospital of North Norway

May 01, 2016

- -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Dec 12, 2016

This variant is denoted BRCA2 c.8323A>G at the cDNA level, p.Met2775Val (M2775V) at the protein level, and results in the change of a Methionine to a Valine (ATG>GTG). Using alternate nomenclature, this variant would be defined as BRCA2 8551A>G. This variant has been observed in at least one individual with a family history of breast or ovarian cancer (Jarhelle 2016). BRCA2 Met2775Val was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, suggesting it is not a common benign variant in these populations. Since Methionine and Valine share similar properties, this is considered a conservative amino acid substitution. BRCA2 Met2775Val occurs at a position that is not conserved and is located in the DNA binding domain (Yang 2002). In silico analyses are inconsistent regarding the effect this variant may have on protein structure and function. Based on currently available evidence, it is unclear whether BRCA2 Met2775Val is a pathogenic or benign variant. We consider it to be a variant of uncertain significance. -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Color Diagnostics, LLC DBA Color Health

Jan 31, 2022

This missense variant replaces methionine with valine at codon 2775 in the DNA binding/OB tower domain 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 not been reported in individuals affected with hereditary cancer in the literature. This variant has been identified in 1/247808 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. -

Hereditary breast ovarian cancer syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Oct 18, 2023

This sequence change replaces methionine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 2775 of the BRCA2 protein (p.Met2775Val). This variant is present in population databases (rs767209209, gnomAD 0.0009%). This missense change has been observed in individual(s) with breast or ovarian cancer (PMID: 27495310). ClinVar contains an entry for this variant (Variation ID: 254645). 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. 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	0.12
BayesDel_addAF	Pathogenic	0.16	D
BayesDel_noAF	Uncertain	0.0
CADD	Benign	18
DANN	Uncertain	0.99
Eigen	Uncertain	0.31
Eigen_PC	Uncertain	0.31
FATHMM_MKL	Pathogenic	0.98	D
M_CAP	Benign	0.078	D
MetaRNN	Uncertain	0.49	T;T
MetaSVM	Uncertain	-0.13	T
MutationTaster	Benign	0.89	D;D
PrimateAI	Uncertain	0.49	T
PROVEAN	Benign	-1.0	N;N
REVEL	Uncertain	0.48
Sift	Uncertain	0.016	D;D
Sift4G	Uncertain	0.024	D;D
Vest4		0.49
MutPred		0.54		Loss of catalytic residue at M2775 (P = 0.0445);Loss of catalytic residue at M2775 (P = 0.0445);
MVP		0.87
MPC		0.037
ClinPred		0.67	D
GERP RS		3.2
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
gMVP		0.56

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

Other links and lift over

dbSNP: rs767209209; hg19: chr13-32937662;