chr13-32319109-G-T

Position:

• chr13-32319109-G-T

Variant summary

Our verdict is Pathogenic. Variant got 19 ACMG points: 19P and 0B. PVS1 PM2 PP3 PP5_Very_Strong

The NM_000059.4(BRCA2):​c.100G>T​(p.Glu34Ter) variant causes a stop gained change. 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. E34E) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 33)
• Consequence: BRCA2 NM_000059.4 stop_gained
• Clinical Significance: Pathogenic reviewed by expert panel P:16
• Conservation: PhyloP100: 7.06

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 19 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
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 13-32319109-G-T is Pathogenic according to our data. Variant chr13-32319109-G-T is described in ClinVar as [Pathogenic]. Clinvar id is 51041.Status of the report is reviewed_by_expert_panel, 3 stars. Variant chr13-32319109-G-T is described in Lovd as [Pathogenic]. Variant chr13-32319109-G-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
BRCA2	NM_000059.4	c.100G>T	p.Glu34Ter	stop_gained	3/27	ENST00000380152.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
BRCA2	ENST00000380152.8	c.100G>T	p.Glu34Ter	stop_gained	3/27	5	NM_000059.4	A2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:16

Revision: reviewed by expert panel

Submissions by phenotype

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

Pathogenic, no assertion criteria provided	clinical testing	Breast Cancer Information Core (BIC) (BRCA2)	Dec 23, 2003	- -
Pathogenic, no assertion criteria provided	clinical testing	BRCAlab, Lund University	Mar 02, 2020	- -
Pathogenic, no assertion criteria provided	clinical testing	Diagnostic Laboratory, Department of Genetics, University Medical Center Groningen	-	- -
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, 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. -

not provided Pathogenic:4

Pathogenic, criteria provided, single submitter	clinical testing	Quest Diagnostics Nichols Institute San Juan Capistrano	Dec 15, 2017	- -
Pathogenic, no assertion criteria provided	clinical testing	Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+	-	- -
Pathogenic, no assertion criteria provided	clinical testing	Clinical Genetics Laboratory, Department of Pathology, Netherlands Cancer Institute	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Mar 19, 2018	This variant is denoted BRCA2 c.100G>T at the cDNA level and p.Glu34Ter (E34X) at the protein level. The substitution creates a nonsense variant, which changes a Glutamic Acid to a premature stop codon (GAA>TAA), and is predicted to cause loss of normal protein function through either protein truncation or nonsense-mediated mRNA decay. This variant, also defined as BRCA2 328G>T using alternate nomenclature, has been reported in association with breast and/or ovarian cancer (van der Hout 2006, Teixeira 2018), as well as in at least one male with prostate and breast cancer (Ibrahim 2018). This variant is considered pathogenic. -

Hereditary breast ovarian cancer syndrome Pathogenic:3

Pathogenic, no assertion criteria provided	research	Research Molecular Genetics Laboratory, Women's College Hospital, University of Toronto	Jan 31, 2014	- -
Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Jan 02, 2022	Variant summary: BRCA2 c.100G>T (p.Glu34X) 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. Truncations downstream of this position have been classified as pathogenic by our laboratory. The variant was absent in 251030 control chromosomes. c.100G>T has been reported in the literature in multiple individuals affected with Hereditary Breast And Ovarian Cancer Syndrome (example, van der Hout_2006, Rebbeck_2018). 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. Multiple clinical diagnostic laboratories, an expert panel (ENIGMA) and a consortium (CIMBA) have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All submitters classified the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Dec 07, 2023	This sequence change creates a premature translational stop signal (p.Glu34*) 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). This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individual(s) with breast and/or ovarian cancer (PMID: 16683254). ClinVar contains an entry for this variant (Variation ID: 51041). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -

Hereditary cancer-predisposing syndrome Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Jun 26, 2023	This variant changes 1 nucleotide in exon 3 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 over twenty individuals with a personal and/or family history of breast or ovarian cancer (PMID: 16683254, 29446198, 29483665) and in an individual affected with breast and prostate cancer (PMID: 29433453). In a large breast cancer case-control meta analysis conducted by the BRIDGES consortium, this variant was reported in 2/60466 cases and 1/53461 controls (PMID: 33471991; Leiden Open Variation Database DB-ID BRCA2_001301). 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, criteria provided, single submitter	clinical testing	Ambry Genetics	May 25, 2023	The p.E34* pathogenic mutation (also known as c.100G>T), located in coding exon 2 of the BRCA2 gene, results from a G to T substitution at nucleotide position 100. This changes the amino acid from a glutamic acid to a stop codon within coding exon 2. This mutation has been described in two Dutch families at increased risk for hereditary breast and ovarian cancer (HBOC) syndrome (van der Hout AH et al. Hum. Mutat. 2006 Jul; 27(7):654-66), and in a male breast cancer patient (Ibrahim M et al. BMC Cancer 2018 02;18(1):179). This alteration was also identified in a large, worldwide study of BRCA1/2 mutation positive families (Rebbeck TR et al. Hum. Mutat. 2018 05;39(5):593-620). RNA studies have demonstrated that this substitution results in abnormal splicing that includes two in-frame transcripts that splice out this alteration and the premature stop codon from final transcript: one transcript that removes the first 15 amino acids from coding exon 2 and one that results in the complete loss of coding exon 2 that is known to be deleterious (Ambry internal data; Caputo SM et al. Oncotarget 2018 Apr;9(25):17334-17348). Current data suggests that the presence of these transcripts is not expected to rescue function. As such, this alteration is interpreted as a disease-causing mutation. -

Medulloblastoma;C0346153:Familial cancer of breast;C0376358:Malignant tumor of prostate;C1838457:Fanconi anemia complementation group D1;C2675520:Breast-ovarian cancer, familial, susceptibility to, 2;C2751641:Glioma susceptibility 3;C3150546:Pancreatic cancer, susceptibility to, 2;CN033288:Wilms tumor 1 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Oct 31, 2018

- -

Familial cancer of breast Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneKor MSA

Jan 01, 2020

This is a single base substitution, replacing the Glutamate at position 34 of the BRCA2 protein by a Termination codon. It results in a truncated non-functional protein. Truncating variants in the BRCA2 gene are known to be pathogenic. This mutation has been previously described in mutation databases (https://research.nhgri.nih.gov/projects/bic) as pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.62	D
BayesDel_noAF	Pathogenic	0.65
CADD	Pathogenic	50
DANN	Uncertain	1.0
Eigen	Pathogenic	1.2
Eigen_PC	Pathogenic	1.1
FATHMM_MKL	Pathogenic	0.97	D
MutationTaster	Benign	1.0	A;A
Vest4		0.69
GERP RS		5.7

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.67		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.62		Position offset: 13
DS_AL_spliceai		0.67		Position offset: -32

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs80358391; hg19: chr13-32893246;