chr13-32319327-T-C

Position:

• chr13-32319327-T-C

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1_Moderate PM2 PP5_Very_Strong

The NM_000059.4(BRCA2):​c.316+2T>C variant causes a splice donor 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. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★★★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: BRCA2 NM_000059.4 splice_donor
• Scores: Splicing: ADA: 0.9869
• Clinical Significance: Pathogenic reviewed by expert panel P:9
• Conservation: PhyloP100: 2.36

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 12 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.02417861 fraction of the gene. No cryptic splice site detected. Exon removal is inframe change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 13-32319327-T-C is Pathogenic according to our data. Variant chr13-32319327-T-C is described in ClinVar as [Pathogenic]. Clinvar id is 51407.Status of the report is reviewed_by_expert_panel, 3 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BRCA2	NM_000059.4	c.316+2T>C		splice_donor_variant		ENST00000380152.8	NP_000050.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
BRCA2	ENST00000380152.8	c.316+2T>C		splice_donor_variant		5	NM_000059.4	ENSP00000369497	A2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:9

Revision: reviewed by expert panel

Submissions by phenotype

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

Pathogenic, no assertion criteria provided	clinical testing	Breast Cancer Information Core (BIC) (BRCA2)	Jun 20, 2002	- -
Pathogenic, reviewed by expert panel	curation	Evidence-based Network for the Interpretation of Germline Mutant Alleles (ENIGMA)	Apr 01, 2018	Almost complete (97%) skipping of exon 3 (r.68_316del) in a minigene splicing assay. Molecular consequence is the same as other variants designated as pathogenic as determined by multifactorial likelihood analysis (PMID: 29707112). Specifically, pathogenic consequence of the in-frame transcript without exon 3 has been shown in another family with a deletion of this exon, by co-segregation analysis with LR >1300:1 in favour of pathogenicity (PMID: 29707112). -

not provided Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Mar 30, 2023	Canonical splice site variant predicted to result in a null allele in a gene for which loss of function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (gnomAD); Observed in individuals with prostate cancer (Momozawa et al., 2019); Truncating variants in this gene are considered pathogenic by a well-established clinical consortium and/or database; Also known as 544+2T>C; This variant is associated with the following publications: (PMID: 28152038, 29707112, 30883759, 34597585, 35979650, 31214711) -
Pathogenic, criteria provided, single submitter	clinical testing	Quest Diagnostics Nichols Institute San Juan Capistrano	Apr 23, 2018	- -

Hereditary breast ovarian cancer syndrome Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Dec 18, 2023	Variant summary: BRCA2 c.316+2T>C is located in a canonical splice-site and is predicted to affect mRNA splicing resulting in a significantly altered protein due to either exon skipping, shortening, or inclusion of intronic material. Several computational tools predict a significant impact on normal splicing: Three predict the variant abolishes a canonical 5' splicing donor site, and two predict the variant creates a cryptic 5' donor site. Publications report experimental evidence that this variant affects mRNA splicing, resulting in deletion of exon 3 (Caputo_2018, Fraile-Bethencourt_2019). The variant was absent in 249688 control chromosomes (gnomAD). c.316+2T>C has been reported in the literature in individuals affected with Hereditary Breast And Ovarian Cancer Syndrome (Caputo_2018, Inagaki-Kawata_2020). The following publications have been ascertained in the context of this evaluation (PMID: 29707112, 30883759, 33067557). Six submitters have cited clinical-significance assessments for this variant to ClinVar after 2014. 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	Labcorp Genetics (formerly Invitae), Labcorp	Jan 24, 2024	This sequence change affects a donor splice site in intron 3 of the BRCA2 gene. RNA analysis indicates that disruption of this splice site induces altered splicing and likely results in a shortened protein product. This variant is not present in population databases (gnomAD no frequency). Disruption of this splice site has been observed in individual(s) with breast cancer (PMID: 29707112). ClinVar contains an entry for this variant (Variation ID: 51407). Studies have shown that disruption of this splice site results in skipping of exon 3, but is expected to preserve the integrity of the reading-frame (PMID: 29707112; Invitae). This variant disrupts the PALB2 binding domain which is critical for maintenance of the DNA repair function (PMID: 16793542, 22678057, 24323938, 19609323, 19369211). While functional studies have not been performed to directly test the effect of this variant on BRCA2 protein function, this suggests that disruption of this region of the protein is causative of disease. For these reasons, this variant has been classified as Pathogenic. -

Gastric cancer Pathogenic:1

Pathogenic, no assertion criteria provided

research

Laboratory for Genotyping Development, RIKEN

Jul 01, 2021

- -

Hereditary cancer-predisposing syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Jun 21, 2021

The c.316+2T>C intronic pathogenic mutation results from a T to C substitution two nucleotides after coding exon 2 in the BRCA2 gene. This mutation has been detected in patients of Asian ancestry with a personal and/or family history of breast and/or ovarian cancer (LaDuca H et al. PLoS One. 2017 Feb 2;12(2):e0170843; Momozawa Y et al. J Natl Cancer Inst, 2020 04;112:369-376; Ambry internal data). This alteration produced coding exon 2 (also known as Exon 3) skipping in multiple minigene assays (Caputo SM et al. Oncotarget, 2018 Apr;9:17334-17348; Fraile-Bethencourt E et al. J Pathol, 2019 08;248:409-420). Other alterations impacting the same donor site (c.315+5G>A and c.316+5G>C, among others) have also been described as producing the same splice defect are considered Class 5 by a multifactorial model of variant interpretation (Caputo SM et al. Oncotarget, 2018 Apr;9:17334-17348). In addition to the clinical data presented in the literature, alterations that disrupt the canonical splice site are expected to cause aberrant splicing, resulting in an abnormal protein or a transcript that is subject to nonsense-mediated mRNA decay. As such, this alteration is classified as a disease-causing mutation. -

Familial cancer of breast Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Baylor Genetics

Mar 06, 2024

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.21	D
BayesDel_noAF	Uncertain	0.060
CADD	Benign	23
DANN	Uncertain	0.99
Eigen	Pathogenic	0.81
Eigen_PC	Uncertain	0.60
FATHMM_MKL	Uncertain	0.86	D
MutationTaster	Benign	1.0	D;D
GERP RS		4.2

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	0.99
dbscSNV1_RF	Benign	0.62
SpliceAI score (max)		0.95		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.95		Position offset: -2

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

Publications

LitVar

Other links and lift over

dbSNP: rs81002805; hg19: chr13-32893464;