chr13-32340590-G-T

Position:

• chr13-32340590-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 4P and 3B. PM1 PM2 BP4_Moderate BP6

The NM_000059.4(BRCA2):​c.6235G>T​(p.Val2079Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 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 Conflicting classifications of pathogenicity (no stars).

• Frequency: Genomes: not found (cov: 32)
• Consequence: BRCA2 NM_000059.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2 B:1
• Conservation: PhyloP100: 0.946

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.

• PM1: In a repeat BRCA2 8 (size 34) in uniprot entity BRCA2_HUMAN there are 4 pathogenic changes around while only 1 benign (80%) in NM_000059.4
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.19731855).
• BP6: Variant 13-32340590-G-T is Benign according to our data. Variant chr13-32340590-G-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 224466.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.6235G>T	p.Val2079Leu	missense_variant	11/27	ENST00000380152.8	NP_000050.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
BRCA2	ENST00000380152.8	c.6235G>T	p.Val2079Leu	missense_variant	11/27	5	NM_000059.4	ENSP00000369497	A2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 48

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:2 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	Ambry Genetics	Dec 14, 2023	The p.V2079L variant (also known as c.6235G>T), located in coding exon 10 of the BRCA2 gene, results from a G to T substitution at nucleotide position 6235. The valine at codon 2079 is replaced by leucine, an amino acid with highly similar properties. This alteration was identified in 1/507 unselected Chinese breast cancer patients (Zhong X et al. PLoS One, 2016 Jun;11:e0156789). This amino acid position is poorly conserved in available vertebrate species. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -
Likely benign, criteria provided, single submitter	curation	University of Washington Department of Laboratory Medicine, University of Washington	Mar 23, 2023	Missense variant in a coldspot region where missense variants are very unlikely to be pathogenic (PMID:31911673). -

Breast neoplasm Uncertain:1

Uncertain significance, criteria provided, single submitter

research

Laboratory of Molecular Diagnosis of Cancer, West China Hospital, Sichuan University

Nov 01, 2015

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.12
BayesDel_addAF	Benign	-0.053	T
BayesDel_noAF	Benign	-0.31
CADD	Benign	15
DANN	Benign	0.96
Eigen	Benign	-0.62
Eigen_PC	Benign	-0.41
FATHMM_MKL	Benign	0.62	D
M_CAP	Uncertain	0.11	D
MetaRNN	Benign	0.20	T;T
MetaSVM	Benign	-1.0	T
MutationTaster	Benign	0.93	N;N
PrimateAI	Benign	0.26	T
PROVEAN	Benign	0.31	N;N
REVEL	Uncertain	0.38
Sift	Benign	0.12	T;T
Sift4G	Benign	0.56	T;T
Vest4		0.36
MutPred		0.44		Gain of helix (P = 0.062);Gain of helix (P = 0.062);
MVP		0.71
MPC		0.020
ClinPred		0.30	T
GERP RS		3.4
gMVP		0.16

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: rs886037812; hg19: chr13-32914727;