rs876658889

chr13-32362650-A-Gchr13-32362650-A-T

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM1 PP3

The NM_000059.4(BRCA2):c.7933A>G(p.Arg2645Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000013 in 1,461,878 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 Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. R2645R) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.000013 (0 hom.)
• Consequence: BRCA2 NM_000059.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:5 B:1
• Conservation: PhyloP100: 2.79

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 Uncertain_significance. Variant got 3 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 3 benign, 17 uncertain in NM_000059.4
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.803

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
BRCA2	NM_000059.4	c.7933A>G	p.Arg2645Gly	missense_variant	17/27	ENST00000380152.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
BRCA2	ENST00000380152.8	c.7933A>G	p.Arg2645Gly	missense_variant	17/27	5	NM_000059.4	A2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.0000119 AC: 3 AN: 251304 Hom.: 0 AF XY: 0.0000147 AC XY: 2 AN XY: 135806

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000578

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: 0.00000880

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000130 AC: 19 AN: 1461878 Hom.: 0 Cov.: 33 AF XY: 0.0000138 AC XY: 10 AN XY: 727238

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000671

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: 0.0000144

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

EpiCase AF: 0.00

EpiControl AF: 0.0000593

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:5 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:1 Benign:1

Likely benign, criteria provided, single submitter	clinical testing	Ambry Genetics	Jan 05, 2022	This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -
Uncertain significance, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Nov 17, 2023	This missense variant replaces arginine with glycine at codon 2645 of the BRCA2 protein. Computational prediction is inconclusive regarding the impact of this variant on protein structure and function (internally defined REVEL score threshold 0.5 < inconclusive < 0.7, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in an individual affected with colorectal cancer (PMID: 27356891), an individual affected with prostate cancer (PMID: 32853339), and in a multifactorial analysis with family history, pathology and segregation likelihood ratios for pathogenicity of 0.24, 0.05, and 2.93, respectively (PMID: 34597585). This variant has been identified in 3/251304 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:1

Uncertain significance, criteria provided, single submitter

clinical testing

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Oct 23, 2023

Variant summary: BRCA2 c.7933A>G (p.Arg2645Gly) results in a non-conservative amino acid change located in the Breast cancer type 2 susceptibility protein, helical domain of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 1.2e-05 in 254522 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.7933A>G has been reported in the literature in individuals affected with Hereditary Breast and/or Ovarian Cancer Syndrome (e.g. Caputo_2021), colorectal cancer (e.g. Dobbins_2016), or prostate cancer (e.g. Darst_2021) without strong evidence for causality. 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: 22505045, 34597585, 32853339, 27356891, 35260348). Four submitters have cited clinical-significance assessments for this variant to ClinVar after 2014, classifying the variant as uncertain significance (n=3) or likely benign (n=1). Based on the evidence outlined above, the variant was classified as uncertain significance. -

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

Uncertain significance, criteria provided, single submitter

clinical testing

All of Us Research Program, National Institutes of Health

Dec 13, 2023

This missense variant replaces arginine with glycine at codon 2645 of the BRCA2 protein. Computational prediction is inconclusive regarding the impact of this variant on protein structure and function (internally defined REVEL score threshold 0.5 < inconclusive < 0.7, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in an individual affected with colorectal cancer (PMID: 27356891), an individual affected with prostate cancer (PMID: 32853339), and in a multifactorial analysis with family history, pathology and segregation likelihood ratios for pathogenicity of 0.24, 0.05, and 2.93, respectively (PMID: 34597585). This variant has been identified in 3/251304 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 provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Quest Diagnostics Nichols Institute San Juan Capistrano

Aug 26, 2021

- -

Hereditary breast ovarian cancer syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jan 28, 2024

This sequence change replaces arginine, which is basic and polar, with glycine, which is neutral and non-polar, at codon 2645 of the BRCA2 protein (p.Arg2645Gly). This variant is present in population databases (no rsID available, gnomAD 0.006%). This missense change has been observed in individual(s) with clinical features of BRCA2-related conditions (PMID: 22505045, 27356891, 32853339, 34597585). ClinVar contains an entry for this variant (Variation ID: 230994). 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%. Studies have shown that this missense change does not affect mRNA splicing (PMID: 22505045). 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	Uncertain	0.37
BayesDel_addAF	Uncertain	0.13	D
BayesDel_noAF	Uncertain	0.12
Cadd	Uncertain	25
Dann	Uncertain	1.0
Eigen	Uncertain	0.63
Eigen_PC	Uncertain	0.60
FATHMM_MKL	Uncertain	0.85	D
M_CAP	Pathogenic	0.29	D
MetaRNN	Pathogenic	0.80	D;D
MetaSVM	Uncertain	0.56	D
MutationTaster	Benign	0.94	D;D
PrimateAI	Benign	0.46	T
PROVEAN	Benign	-1.9	N;N
REVEL	Uncertain	0.63
Sift	Uncertain	0.0010	D;D
Sift4G	Uncertain	0.0050	D;D
Vest4		0.66
MutPred		0.69		Loss of phosphorylation at S2648 (P = 0.0667);Loss of phosphorylation at S2648 (P = 0.0667);
MVP		0.95
MPC		0.18
ClinPred		0.90	D
GERP RS		4.5
gMVP		0.49

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: rs876658889; hg19: chr13-32936787;