chr13-32379767-C-T

Position:

• chr13-32379767-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_000059.4(BRCA2):​c.8971C>T​(p.Arg2991Cys) variant causes a missense change. The variant allele was found at a frequency of 0.00000343 in 1,459,270 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000034 (0 hom.)
• Consequence: BRCA2 NM_000059.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3 B:1
• Conservation: PhyloP100: 4.37

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 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BRCA2	NM_000059.4	c.8971C>T	p.Arg2991Cys	missense_variant	23/27	ENST00000380152.8	NP_000050.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
BRCA2	ENST00000380152.8	c.8971C>T	p.Arg2991Cys	missense_variant	23/27	5	NM_000059.4	ENSP00000369497.3
BRCA2	ENST00000530893.7	c.8602C>T	p.Arg2868Cys	missense_variant	23/27	1		ENSP00000499438.2
BRCA2	ENST00000614259.2	n.*1029C>T		non_coding_transcript_exon_variant	22/26	2		ENSP00000506251.1
BRCA2	ENST00000614259.2	n.*1029C>T		3_prime_UTR_variant	22/26	2		ENSP00000506251.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000798 AC: 2 AN: 250750 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135532

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000544

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000884

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000343 AC: 5 AN: 1459270 Hom.: 0 Cov.: 31 AF XY: 0.00000413 AC XY: 3 AN XY: 726088

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000504

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000180

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 32

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:1 Benign:1

Uncertain significance, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Nov 21, 2023	This missense variant replaces arginine with cysteine at codon 2991 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). Functional studies have shown that this variant does not impact the homology directed repair activity of BRCA2 protein (PMID: 29884841, 33609447). This variant has been reported in individuals with a personal or family history of breast or ovarian cancer (PMID: 27062684, 33471991). One of these individuals also carried a pathogenic mutation that could explain the observed phenotype. This variant has also been reported in an individual affected with colon cancer with tumor showing high microsatellite instability (PMID: 28591715). This variant has been identified in 2/250750 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. -
Likely benign, criteria provided, single submitter	clinical testing	Ambry Genetics	Dec 06, 2019	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. -

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 18, 2023

This missense variant replaces arginine with cysteine at codon 2991 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). Splice site prediction tools suggest that this variant may not impact RNA splicing. A functional study has shown that this variant does not impact the homology directed repair activity of BRCA2 protein (PMID: 29884841). This variant has been reported in individuals from high risk breast and/or ovarian cancer families (PMID: 27062684). One of these individuals also carried a pathogenic mutation that could explain the observed phenotype. This variant has also been reported in an individual affected with colon cancer with tumor showing high microsatellite instability (PMID: 28591715). This variant has been identified in 2/250750 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

Labcorp Genetics (formerly Invitae), Labcorp

Dec 23, 2023

This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 2991 of the BRCA2 protein (p.Arg2991Cys). This variant is present in population databases (rs751787816, gnomAD 0.006%). This missense change has been observed in individual(s) with BRCA2-related conditions (PMID: 27062684, 35171259). ClinVar contains an entry for this variant (Variation ID: 489793). Advanced modeling performed at Invitae incorporating data from internal and/or published experimental studies (PMID: 33609447) indicates that this missense variant is not expected to disrupt BRCA2 function with a negative predictive value of 95%. Experimental studies have shown that this missense change does not substantially affect BRCA2 function (PMID: 29884841). RNA analysis performed to evaluate the impact of this missense change on mRNA splicing indicates it does not significantly alter splicing (Invitae). 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	0.20
BayesDel_addAF	Benign	-0.068	T
BayesDel_noAF	Benign	-0.17
CADD	Uncertain	25
DANN	Uncertain	1.0
Eigen	Uncertain	0.20
Eigen_PC	Benign	0.22
FATHMM_MKL	Pathogenic	0.97	D
M_CAP	Uncertain	0.24	D
MetaRNN	Uncertain	0.45	T;T
MetaSVM	Uncertain	-0.27	T
PrimateAI	Benign	0.39	T
PROVEAN	Benign	-1.8	N;N
REVEL	Uncertain	0.56
Sift	Benign	0.037	D;D
Sift4G	Pathogenic	0.0	D;D
Vest4		0.44
MutPred		0.59		Loss of MoRF binding (P = 0.0078);Loss of MoRF binding (P = 0.0078);
MVP		0.88
MPC		0.044
ClinPred		0.79	D
GERP RS		3.9
gMVP		0.63

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.17		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: rs751787816; hg19: chr13-32953904; COSMIC: COSV66452721; COSMIC: COSV66452721;