13-32336300-C-T

Position:

• chr13-32336300-C-T

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000059.4(BRCA2):​c.1945C>T​(p.Gln649*) 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 (★★★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 32)
• Consequence: BRCA2 NM_000059.4 stop_gained
• Clinical Significance: Pathogenic reviewed by expert panel P:12
• Conservation: PhyloP100: 0.907

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]

BRCA2 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 13-32336300-C-T is Pathogenic according to our data. Variant chr13-32336300-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 91764.Status of the report is reviewed_by_expert_panel, 3 stars. Variant chr13-32336300-C-T is described in Lovd as [Pathogenic]. Variant chr13-32336300-C-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BRCA2	NM_000059.4	c.1945C>T	p.Gln649*	stop_gained	11/27	ENST00000380152.8	NP_000050.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
BRCA2	ENST00000380152.8	c.1945C>T	p.Gln649*	stop_gained	11/27	5	NM_000059.4	ENSP00000369497.3
BRCA2	ENST00000530893.7	c.1576C>T	p.Gln526*	stop_gained	11/27	1		ENSP00000499438.2
BRCA2	ENST00000614259.2	n.1945C>T		non_coding_transcript_exon_variant	10/26	2		ENSP00000506251.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:12

Revision: reviewed by expert panel

Submissions by phenotype

Breast-ovarian cancer, familial, susceptibility to, 2 Pathogenic:5

Pathogenic, criteria provided, single submitter	clinical testing	All of Us Research Program, National Institutes of Health	Oct 09, 2023	This variant changes 1 nucleotide in exon 11 of the BRCA2 gene, creating a premature translation stop signal. This variant is expected to result in an absent or non-functional protein product. To our knowledge, functional studies have not been reported for this variant. This variant has been reported in individuals affected with breast cancer (PMID: 28423363). This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). Loss of BRCA2 function is a known mechanism of disease (clinicalgenome.org). Based on the available evidence, this variant is classified as Pathogenic. -
Pathogenic, reviewed by expert panel	curation	Evidence-based Network for the Interpretation of Germline Mutant Alleles (ENIGMA)	Sep 08, 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	- -
Pathogenic, criteria provided, single submitter	clinical testing	Department of Medical Genetics, Oslo University Hospital	Jul 01, 2015	- -
Pathogenic, no assertion criteria provided	clinical testing	Sharing Clinical Reports Project (SCRP)	Aug 29, 2008	- -

Hereditary breast ovarian cancer syndrome Pathogenic:3

Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jun 21, 2023	ClinVar contains an entry for this variant (Variation ID: 91764). This premature translational stop signal has been observed in individual(s) with breast cancer (PMID: 28423363, 29339979, 29446198). This variant is not present in population databases (gnomAD no frequency). This sequence change creates a premature translational stop signal (p.Gln649*) in the BRCA2 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in BRCA2 are known to be pathogenic (PMID: 20104584). For these reasons, this variant has been classified as Pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Dec 11, 2020	Variant summary: BRCA2 c.1945C>T (p.Gln649X) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. The variant was absent in 240878 control chromosomes (gnomAD). c.1945C>T has been reported in the literature in multiple individuals affected with Hereditary Breast and Ovarian Cancer Syndrome as well as in individuals undergoing testing (Rebbeck_2018, Heramb_2018, Tedaldi_2017). These data indicate that the variant is very likely to be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Six ClinVar submitters (evaluation after 2014) including an expert panel (ENIGMA) cite the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -
Pathogenic, no assertion criteria provided	research	Research Molecular Genetics Laboratory, Women's College Hospital, University of Toronto	Jan 31, 2014	- -

Familial cancer of breast Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Nov 11, 2021	- -
Pathogenic, criteria provided, single submitter	clinical testing	Institute of Human Genetics, University of Leipzig Medical Center	Jan 01, 2019	- -

Hereditary cancer-predisposing syndrome Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Ambry Genetics	Jun 12, 2023	The p.Q649* pathogenic mutation (also known as c.1945C>T), located in coding exon 10 of the BRCA2 gene, results from a C to T substitution at nucleotide position 1945. This changes the amino acid from a glutamine to a stop codon within coding exon 10. This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). This alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. As such, this alteration is interpreted as a disease-causing mutation. -
Pathogenic, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Aug 30, 2023	This variant changes 1 nucleotide in exon 11 of the BRCA2 gene, creating a premature translation stop signal. This variant is expected to result in an absent or non-functional protein product. This variant has been reported in an individual affected with DCIS (PMID: 28423363) and has been identified in 3 families among the CIMBA participants (PMID: 29446198). This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). Loss of BRCA2 function is a known mechanism of disease (clinicalgenome.org). Based on the available evidence, this variant is classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.37	D
BayesDel_noAF	Pathogenic	0.29
CADD	Pathogenic	34
DANN	Uncertain	1.0
Eigen	Uncertain	0.41
Eigen_PC	Benign	0.12
FATHMM_MKL	Benign	0.18	N
Vest4		0.88
GERP RS		5.0

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs398122735; hg19: chr13-32910437;