rs1555289992

Positions:

• chr13-32398398-GA-G

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PVS1_Strong PM2 PP5_Moderate

The NM_000059.4(BRCA2):​c.9887delA​(p.Lys3296fs) variant causes a frameshift change. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★). Synonymous variant affecting the same amino acid position (i.e. K3296K) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: BRCA2 NM_000059.4 frameshift
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 6.42

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 Likely_pathogenic. Variant got 8 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. There are 9 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 13-32398398-GA-G is Pathogenic according to our data. Variant chr13-32398398-GA-G is described in ClinVar as [Pathogenic]. Clinvar id is 531239.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BRCA2	NM_000059.4	c.9887delA	p.Lys3296fs	frameshift_variant	27/27	ENST00000380152.8	NP_000050.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
BRCA2	ENST00000380152.8	c.9887delA	p.Lys3296fs	frameshift_variant	27/27	5	NM_000059.4	ENSP00000369497.3
BRCA2	ENST00000530893.7	c.9518delA	p.Lys3173fs	frameshift_variant	27/27	1		ENSP00000499438.2
BRCA2	ENST00000614259.2	n.*1945delA		non_coding_transcript_exon_variant	26/26	2		ENSP00000506251.1
BRCA2	ENST00000614259.2	n.*1945delA		3_prime_UTR_variant	26/26	2		ENSP00000506251.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hereditary breast ovarian cancer syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Dec 13, 2020

For these reasons, this variant has been classified as Pathogenic. This variant is expected to partially affect the amino acid residues Ala3270-Gly3305, which are critical for RAD51-mediated DNA repair activity of the BRCA2 protein (PMID: 17515903, 24323938). Two different truncations downstream of this variant (p.Gln3299*, p.Tyr3308*) have been determined to be pathogenic (PMID: 17026620, 22711857, 18593900, 18607349, Invitae). This suggests that deletion of this region of the BRCA2 protein is causative of disease. This variant has not been reported in the literature in individuals with BRCA2-related disease. ClinVar contains an entry for this variant (Variation ID: 531239). This variant is not present in population databases (ExAC no frequency). This sequence change results in a premature translational stop signal in the BRCA2 gene (p.Lys3296Argfs*17). While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 123 amino acids of the BRCA2 protein. -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		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: rs1555289992; hg19: chr13-32972535;