13-32339720-A-T

Variant names:

• chr13-32339720-A-T
• rs587782240
• NM_000059.4:c.5365A>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.5365A>T​(p.Lys1789*) 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: 33)
• Consequence: BRCA2 NM_000059.4 stop_gained
• Clinical Significance: Pathogenic reviewed by expert panel P:3
• Conservation: PhyloP100: 0.0140

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: 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 13-32339720-A-T is Pathogenic according to our data. Variant chr13-32339720-A-T is described in ClinVar as [Pathogenic]. Clinvar id is 266875.Status of the report is reviewed_by_expert_panel, 3 stars. Variant chr13-32339720-A-T is described in Lovd as [Pathogenic]. Variant chr13-32339720-A-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
BRCA2	NM_000059.4	c.5365A>T	p.Lys1789*	stop_gained	Exon 11 of 27	ENST00000380152.8	NP_000050.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
BRCA2	ENST00000380152.8	c.5365A>T	p.Lys1789*	stop_gained	Exon 11 of 27	5	NM_000059.4	ENSP00000369497.3
BRCA2	ENST00000530893.7	c.4996A>T	p.Lys1666*	stop_gained	Exon 11 of 27	1		ENSP00000499438.2
BRCA2	ENST00000614259.2	n.5365A>T		non_coding_transcript_exon_variant	Exon 10 of 26	2		ENSP00000506251.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 45

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3

Revision: reviewed by expert panel

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

- -

Oct 18, 2016

Evidence-based Network for the Interpretation of Germline Mutant Alleles (ENIGMA)

Significance: Pathogenic

Review Status: reviewed by expert panel

Collection Method: curation

Variant allele predicted to encode a truncated non-functional protein. -

Hereditary breast ovarian cancer syndrome Pathogenic:1

Oct 14, 2019

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.Lys1789X variant in BRCA2 has not been previously reported in individuals with hereditary breast and/or ovarian cancer (HBOC) and was absent from large population studies, but has been reported in ClinVar (Variation ID: 266875). This nonsense variant leads to a premature termination codon at position 1789, which is predicted to lead to a truncated or absent protein. Loss of function of the BRCA2 gene is an established disease mechanism in autosomal dominant HBOC. In summary, although additional studies are required to fully establish its clinical significance, this variant meets criteria to be classified as likely pathogenic for autosomal dominant HBOC. ACMG/AMP Criteria applied: PVS1, PM2. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.35	D
BayesDel_noAF	Pathogenic	0.27
CADD	Pathogenic	27
DANN	Benign	0.94
Eigen	Benign	-0.26
Eigen_PC	Benign	-0.61
FATHMM_MKL	Benign	0.010	N
Vest4		0.91
GERP RS		-1.1

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: rs587782240; hg19: chr13-32913857;