chr13-32326615-T-A

Variant names:

• chr13-32326615-T-A
• rs81002899
• NM_000059.4:c.631+2T>A

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.631+2T>A variant causes a splice donor, intron change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: BRCA2 NM_000059.4 splice_donor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 5.38

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 18 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, No cryptic splice site detected. Exon removal results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 13-32326615-T-A is Pathogenic according to our data. Variant chr13-32326615-T-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 267653.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr13-32326615-T-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
BRCA2	NM_000059.4	c.631+2T>A		splice_donor_variant, intron_variant	Intron 7 of 26	ENST00000380152.8	NP_000050.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
BRCA2	ENST00000380152.8	c.631+2T>A		splice_donor_variant, intron_variant	Intron 7 of 26	5	NM_000059.4	ENSP00000369497.3
BRCA2	ENST00000530893.7	c.262+2T>A		splice_donor_variant, intron_variant	Intron 7 of 26	1		ENSP00000499438.2
BRCA2	ENST00000614259.2	n.631+2T>A		splice_donor_variant, intron_variant	Intron 6 of 25	2		ENSP00000506251.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 29

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

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

Oct 02, 2015

Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA), c/o University of Cambridge

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jul 11, 2017

Counsyl

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Pathogenic:1

May 29, 2018

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is denoted BRCA2 c.631+2T>A or IVS7+2T>A and consists of a T>A nucleotide substitution at the +2 position of intron 7 of the BRCA2 gene. Using alternate nomenclature, this variant would be defined as BRCA2 859+2T>A. This variant destroys a canonical splice donor site and is predicted to cause abnormal gene splicing, leading to either an abnormal message that is subject to nonsense-mediated mRNA decay or to an abnormal protein product. While BRCA2 c.631+2T>A has not, to our knowledge, been reported in the literature, another variant at the same position, BRCA2 c.631+2T>G, has been observed in individuals with hereditary breast and/or ovarian cancer syndrome, with functional studies revealing impacts on splicing and protein expression (Pyne 2000, Biswas 2011, Wong-Brown 2015). Based on the current evidence, we consider BRCA2 c.631+2T>A to be pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.27	D
BayesDel_noAF	Pathogenic	0.15
CADD	Pathogenic	30
DANN	Uncertain	0.98
Eigen	Pathogenic	0.94
Eigen_PC	Pathogenic	0.78
FATHMM_MKL	Pathogenic	0.99	D
GERP RS		4.5

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		0.82		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.82		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: rs81002899; hg19: chr13-32900752;