rs876658955

Positions:

• chr13-32379459-T-C

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 2P and 1B. PM2 BP6

The NM_000059.4(BRCA2):​c.8897T>C​(p.Val2966Ala) variant causes a missense change. The variant allele was found at a frequency of 0.00000205 in 1,461,174 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: 33)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: BRCA2 NM_000059.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3 B:1
• Conservation: PhyloP100: 6.36

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 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP6: Variant 13-32379459-T-C is Benign according to our data. Variant chr13-32379459-T-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 231093.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=1, Uncertain_significance=2}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BRCA2	NM_000059.4	c.8897T>C	p.Val2966Ala	missense_variant	22/27	ENST00000380152.8	NP_000050.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
BRCA2	ENST00000380152.8	c.8897T>C	p.Val2966Ala	missense_variant	22/27	5	NM_000059.4	ENSP00000369497	A2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000400 AC: 1 AN: 249904 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135110

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: 0.00000887

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461174 Hom.: 0 Cov.: 31 AF XY: 0.00000413 AC XY: 3 AN XY: 726868

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: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

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

Likely benign, criteria provided, single submitter	clinical testing	Ambry Genetics	Mar 04, 2020	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	Dec 05, 2019	This missense variant replaces valine with alanine at codon 2966 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. Functional studies have shown this variant as functionally proficient in homology-directed DNA repair and rescue of cisplatin sensitivity assays (PMID: 29884841, 29988080). This variant has been reported in individual(s) who met Dutch clinical genetic testing guideline (PMID: 29988080). This variant has been identified in 1/249904 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, no assertion criteria provided

clinical testing

Department of Pathology and Laboratory Medicine, Sinai Health System

-

The BRCA2 p.Val2966Ala variant was identified in the literature however the frequency of this variant in an affected population was not provided (Mesman 2019). The variant was also identified in dbSNP (ID: rs876658955) as "With Uncertain significance allele", ClinVar (classified as uncertain significance by Ambry Genetics and Invitae).The variant was not identified in the LOVD 3.0 or UMD-LSDB databases. The variant was identified in control databases in 1 of 244734 chromosomes at a frequency of 0.000004 (Genome Aggregation Database Feb 27, 2017). The variant was observed in the following populations: European Non-Finnish in 1 of 110710 chromosomes (freq: 0.000009), while the variant was not observed in the African, Other, Latino, Ashkenazi Jewish, East Asian, European Finnish, and South Asian populations. In a mouse embryonic stem cell (mESC)-based functional assay evaluating complementation by BRCA2 variants of the cell lethal phenotype imposed by Cre-mediated loss of Brca2 as visualized by methylene blue (MB) staining of arising hypoxanthine–aminopterin–thymidine (HAT) resistant clones, as well as homology directed repair (HDR) and sensitivity to the DNA crosslinking agent cisplatin, this variant demonstrated positive MB staining, 62% HDR activity and 65% cisplatin sensitivity, which was comparable to the nonpathogenic variants tested, and suggests a more neutral role for this variant (Mesman 2019). The p.Val2966 residue is conserved in mammals and computational analyses (PolyPhen-2, SIFT, AlignGVGD, BLOSUM, MutationTaster) provide inconsistent predictions regarding the impact to the protein; this information is not very predictive of pathogenicity. The variant occurs outside of the splicing consensus sequence and in silico or computational prediction software programs (SpliceSiteFinder, MaxEntScan, NNSPLICE, GeneSplicer) do not predict a difference in splicing. In summary, based on the above information the clinical significance of this variant cannot be determined with certainty at this time. 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

Sep 22, 2022

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. Advanced modeling of experimental studies (such as gene expression, population dynamics, functional pathways, and cell-cycle effects in cell culture) performed at Invitae indicates that this missense variant is not expected to disrupt BRCA2 protein function. ClinVar contains an entry for this variant (Variation ID: 231093). This variant has not been reported in the literature in individuals affected with BRCA2-related conditions. This variant is present in population databases (no rsID available, gnomAD 0.0009%). This sequence change replaces valine, which is neutral and non-polar, with alanine, which is neutral and non-polar, at codon 2966 of the BRCA2 protein (p.Val2966Ala). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.61
BayesDel_addAF	Pathogenic	0.25	D
BayesDel_noAF	Uncertain	0.12
CADD	Uncertain	25
DANN	Uncertain	1.0
Eigen	Uncertain	0.66
Eigen_PC	Uncertain	0.56
FATHMM_MKL	Uncertain	0.97	D
M_CAP	Uncertain	0.15	D
MetaRNN	Uncertain	0.71	D;D
MetaSVM	Uncertain	0.18	D
MutationTaster	Benign	1.0	D;D
PrimateAI	Benign	0.46	T
PROVEAN	Benign	-1.2	N;N
REVEL	Uncertain	0.42
Sift	Pathogenic	0.0	D;D
Sift4G	Uncertain	0.0060	D;D
Vest4		0.58
MutPred		0.45		Loss of stability (P = 0.0071);Loss of stability (P = 0.0071);
MVP		0.89
MPC		0.17
ClinPred		0.97	D
GERP RS		5.6
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

Other links and lift over

dbSNP: rs876658955; hg19: chr13-32953596;