rs4987049

Positions:

• chr13-32398437-C-A
• chr13-32398437-C-G
• chr13-32398437-C-T

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PVS1_Strong PM2 PP5_Very_Strong

The NM_000059.4(BRCA2):​c.9924C>A​(p.Tyr3308Ter) variant causes a stop gained change involving the alteration of a non-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 Pathogenic (★★★). Synonymous variant affecting the same amino acid position (i.e. Y3308Y) has been classified as Benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: BRCA2 NM_000059.4 stop_gained
• Clinical Significance: Pathogenic reviewed by expert panel P:3
• Conservation: PhyloP100: -1.53

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 Pathogenic. Variant got 14 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. There are 12 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 13-32398437-C-A is Pathogenic according to our data. Variant chr13-32398437-C-A is described in ClinVar as [Pathogenic]. Clinvar id is 267177.Status of the report is reviewed_by_expert_panel, 3 stars. Variant chr13-32398437-C-A is described in Lovd as [Pathogenic]. Variant chr13-32398437-C-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
BRCA2	NM_000059.4	c.9924C>A	p.Tyr3308Ter	stop_gained	27/27	ENST00000380152.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
BRCA2	ENST00000380152.8	c.9924C>A	p.Tyr3308Ter	stop_gained	27/27	5	NM_000059.4	A2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3

Revision: reviewed by expert panel

Submissions by phenotype

Breast-ovarian cancer, familial, susceptibility to, 2 Pathogenic:2

Pathogenic, reviewed by expert panel	curation	Evidence-based Network for the Interpretation of Germline Mutant Alleles (ENIGMA)	Oct 18, 2016	Variant allele predicted to encode a truncated non-functional protein. -
Pathogenic, criteria provided, single submitter	clinical testing	Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA), c/o University of Cambridge	Oct 02, 2015	- -

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Jan 17, 2017

This variant is denoted BRCA2 c.9924C>A at the cDNA level and p.Tyr3308Ter (Y3308X) at the protein level. The substitution creates a nonsense variant, which changes a Tyrosine to a premature stop codon (TAC>TAA), and is predicted to cause loss of normal protein function through protein truncation. Even though this frameshift occurs near the end of the gene and nonsense-mediated decay is not expected to occur, it is significant since the last 111 amino acids are no longer translated causing loss of the NLS2 (Borg 2010). BRCA2 Tyr3308Ter due to an alternate nucleotide substitution (c.9924C>G) at the same position, has been observed in several individuals with Hereditary Breast and Ovarian Cancer (Naseem 2006, Alsop 2012). In addition, functional studies of this truncating variant, including assays measuring sensitivity to DNA damaging agents, homologous recombination, genomic instability and RAD51 focus formation all confirm the pathogenicity of this variant (Hucl 2008, Kuznetsov 2008). Based on currently available evidence, we consider this variant to be pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.35	D
BayesDel_noAF	Pathogenic	0.27
CADD	Pathogenic	33
DANN	Benign	0.94
Eigen	Benign	-0.25
Eigen_PC	Benign	-0.57
FATHMM_MKL	Benign	0.067	N
MutationTaster	Benign	1.0	A;D
Vest4		0.64
GERP RS		-1.6

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: rs4987049; hg19: chr13-32972574;