13-32370433-G-C

Position:

• chr13-32370433-G-C

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PM1 PM2 PM5 PP3_Moderate PP5

The NM_000059.4(BRCA2):​c.8363G>C​(p.Trp2788Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. W2788C) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: BRCA2 NM_000059.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2 U:2
• Conservation: PhyloP100: 9.94

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 Likely_pathogenic. Variant got 9 ACMG points.

• PM1: In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 4 benign, 16 uncertain in NM_000059.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr13-32370432-T-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 52563.We mark this variant Likely_pathogenic, oryginal submissions are: {Likely_pathogenic=2, Uncertain_significance=2}.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.906
• PP5: Variant 13-32370433-G-C is Pathogenic according to our data. Variant chr13-32370433-G-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 52565.We mark this variant Likely_pathogenic, oryginal submissions are: {Likely_pathogenic=2, Uncertain_significance=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
BRCA2	NM_000059.4	c.8363G>C	p.Trp2788Ser	missense_variant	19/27	ENST00000380152.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
BRCA2	ENST00000380152.8	c.8363G>C	p.Trp2788Ser	missense_variant	19/27	5	NM_000059.4	A2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:2 Uncertain:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Hereditary cancer-predisposing syndrome Pathogenic:1 Uncertain:1

Likely pathogenic, criteria provided, single submitter	clinical testing	Ambry Genetics	Apr 16, 2021	The p.W2788S variant (also known as c.8363G>C), located in coding exon 18 of the BRCA2 gene, results from a G to C substitution at nucleotide position 8363. The tryptophan at codon 2788 is replaced by serine, an amino acid with highly dissimilar properties. This alteration, as well as a close match alteration at the same codon (p.W2788R) were found non-functional in a homology-directed DNA repair (HDR) assay (Guidugli L et al. Am. J. Hum. Genet., 2018 02;102:233-248). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Based on the majority of available evidence to date, this variant is likely to be pathogenic. -
Uncertain significance, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Jan 24, 2022	This missense variant replaces tryptophan with serine at codon 2788 of the BRCA2 protein. Computational prediction suggests that this variant may have deleterious impact on protein structure and function (internally defined REVEL score threshold >= 0.7, PMID: 27666373). Functional studies have shown that this variant reduces BRCA2 function in homology-mediated repair assays (PMID: 29394989, 33609447). To our knowledge, this variant has not been reported in individuals affected with hereditary cancer in the literature. This variant has not been identified 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 Pathogenic:1

Likely pathogenic, criteria provided, single submitter

curation

Cancer Variant Interpretation Group UK, Institute of Cancer Research, London

Nov 23, 2018

Data used in classification: The frequency of this variant is 0/138,632 individuals (gnomAD) (PM2_mod). This variant is predicted deleterious on AlignGVGD (class: C65), SIFT (Deleterious), Polyphen2 HumVar (probably damaging) and CADD (23.3) (PP3_sup). The variant is in the DNA-binding domain of BRCA2 (PM1_sup). In the VarCall Bayesian statistical model for VUS classification using functional assay data (Guidugli et al Am J Hum Genet 2018; 102:233-248, Couch Lab), the variant has a probability of being deleterious of 0.99 and an overall classification of pathogenic (PS3_strong). Data not used in classification: There are additional reports of this variant in ClinVar (1), BIC (1), and BRCA2 LOVD (1). -

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

Uncertain significance, no assertion criteria provided

clinical testing

Breast Cancer Information Core (BIC) (BRCA2)

Dec 23, 2003

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.70
BayesDel_addAF	Pathogenic	0.33	D
BayesDel_noAF	Pathogenic	0.24
CADD	Pathogenic	29
DANN	Uncertain	0.99
Eigen	Pathogenic	0.97
Eigen_PC	Pathogenic	0.90
FATHMM_MKL	Pathogenic	1.0	D
M_CAP	Pathogenic	0.32	D
MetaRNN	Pathogenic	0.91	D;D
MetaSVM	Uncertain	0.71	D
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.67	T
PROVEAN	Uncertain	-4.2	D;D
REVEL	Pathogenic	0.74
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0	D;D
Vest4		0.68
MutPred		0.71		Gain of disorder (P = 0);Gain of disorder (P = 0);
MVP		0.96
MPC		0.19
ClinPred		1.0	D
GERP RS		5.2
gMVP		0.92

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		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: rs80359080; hg19: chr13-32944570;