chr13-32363270-G-A

Position:

• chr13-32363270-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 4P and 2B. PM2 PM5 BP4_Moderate

The NM_000059.4(BRCA2):​c.8068G>A​(p.Val2690Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000274 in 1,461,840 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/19 in silico tools predict a benign outcome for this variant. 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. V2690F) has been classified as Pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: BRCA2 NM_000059.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:4
• Conservation: PhyloP100: 0.377

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 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr13-32363270-G-T is described in Lovd as [Pathogenic].
• BP4: Computational evidence support a benign effect (MetaRNN=0.2056672).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BRCA2	NM_000059.4	c.8068G>A	p.Val2690Ile	missense_variant	18/27	ENST00000380152.8	NP_000050.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
BRCA2	ENST00000380152.8	c.8068G>A	p.Val2690Ile	missense_variant	18/27	5	NM_000059.4	ENSP00000369497	A2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251244 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135796

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000289

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: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1461840 Hom.: 0 Cov.: 31 AF XY: 0.00000275 AC XY: 2 AN XY: 727218

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000224

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: 0.00000180

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 32

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

Sharing Clinical Reports Project (SCRP)

Aug 06, 2009

- -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Dec 14, 2017

This variant is denoted BRCA2 c.8068G>A at the cDNA level, p.Val2690Ile (V2690I) at the protein level, and results in the change of a Valine to an Isoleucine (GTT>ATT). Using alternate nomenclature, this variant would be defined as BRCA2 8296G>A. This variant has not, to our knowledge, been published in the literature as pathogenic or benign. BRCA2 Val2690Ile was not observed at a significant allele frequency in large population cohorts (Lek 2016). Since Valine and Isoleucine share similar properties, this is considered a conservative amino acid substitution. BRCA2 Val2690Ile is located within the DNA binding and the nuclear exporting signal (Yang 2002, Jeyasekharan 2013). In-silico analyses, including protein predictors and evolutionary conservation, support that this variant does not alter protein structure/function. Based on currently available evidence, it is unclear whether BRCA2 Val2690Ile is pathogenic or benign. We consider it to be a variant of uncertain significance. -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Mar 23, 2023

The p.V2690I variant (also known as c.8068G>A), located in coding exon 17 of the BRCA2 gene, results from a G to A substitution at nucleotide position 8068. The valine at codon 2690 is replaced by isoleucine, an amino acid with highly similar properties. This amino acid position is not well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Hereditary breast ovarian cancer syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 07, 2021

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 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. ClinVar contains an entry for this variant (Variation ID: 156175). This variant has not been reported in the literature in individuals affected with BRCA2-related conditions. This variant is present in population databases (rs587776471, gnomAD 0.003%). This sequence change replaces valine, which is neutral and non-polar, with isoleucine, which is neutral and non-polar, at codon 2690 of the BRCA2 protein (p.Val2690Ile). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.068
BayesDel_addAF	Benign	-0.013	T
BayesDel_noAF	Benign	-0.17
CADD	Benign	13
DANN	Uncertain	0.99
Eigen	Benign	-0.58
Eigen_PC	Benign	-0.43
FATHMM_MKL	Uncertain	0.81	D
M_CAP	Benign	0.034	D
MetaRNN	Benign	0.21	T;T
MetaSVM	Benign	-0.82	T
MutationTaster	Benign	0.79	N;N
PrimateAI	Benign	0.27	T
PROVEAN	Benign	-0.19	N;N
REVEL	Uncertain	0.43
Sift	Benign	0.64	T;T
Sift4G	Benign	0.93	T;T
Vest4		0.47
MutPred		0.62		Loss of sheet (P = 0.0457);Loss of sheet (P = 0.0457);
MVP		0.76
MPC		0.020
ClinPred		0.11	T
GERP RS		1.3
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
gMVP		0.23

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: rs587776471; hg19: chr13-32937407;