13-32370483-TTAT-TC

Position:

• chr13-32370483-TTAT-TC

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.8414_8416delinsC​(p.Leu2805SerfsTer6) variant causes a frameshift change involving the alteration of a conserved nucleotide. 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. L2805L) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 32)
• Consequence: BRCA2 NM_000059.4 frameshift
• Clinical Significance: Pathogenic reviewed by expert panel P:10
• Conservation: PhyloP100: 7.95

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 13-32370484-TAT-C is Pathogenic according to our data. Variant chr13-32370484-TAT-C is described in ClinVar as [Pathogenic]. Clinvar id is 38159.Status of the report is reviewed_by_expert_panel, 3 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
BRCA2	NM_000059.4	c.8414_8416delinsC	p.Leu2805SerfsTer6	frameshift_variant	19/27	ENST00000380152.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
BRCA2	ENST00000380152.8	c.8414_8416delinsC	p.Leu2805SerfsTer6	frameshift_variant	19/27	5	NM_000059.4	A2

Frequencies

GnomAD3 genomes Cov.: 32

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:10

Revision: reviewed by expert panel

Submissions by phenotype

Breast-ovarian cancer, familial, susceptibility to, 2 Pathogenic:3

Pathogenic, no assertion criteria provided	clinical testing	Sharing Clinical Reports Project (SCRP)	Oct 12, 2008	- -
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:2

Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Mar 27, 2024	Frameshift variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss of function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (gnomAD); Truncating variants in this gene are considered pathogenic by a well-established clinical consortium and/or database; Observed in individuals with BRCA2-related cancers (PMID: 26150619, 36315513); Also known as 8642del3insC; This variant is associated with the following publications: (PMID: 26150619, 12942367, 29446198, 30787465, 36315513) -
Pathogenic, criteria provided, single submitter	clinical testing	Quest Diagnostics Nichols Institute San Juan Capistrano	Aug 09, 2019	The variant results in a shift of the reading frame, and is therefore predicted to result in the loss of a functional protein. Found in at least one symptomatic patient, and not found in general population data. -

Hereditary cancer-predisposing syndrome Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Ambry Genetics	Aug 13, 2021	The c.8414_8416delTATinsC pathogenic mutation, located in coding exon 18 of the BRCA2 gene, results from the deletion of 3 nucleotides and insertion of one nucleotide causing a translational frameshift with a predicted alternate stop codon (p.L2805Sfs*6). This pathogenic mutation, referred to as 8642del3insC, was detected in a male patient who had a personal history of prostate cancer, breast cancer, and GIST (Waisbren J et al. BMJ Case Rep. 2015 Jul;2015). This alteration was identified in a large, worldwide study of BRCA1/2 mutation positive families (Rebbeck TR et al. Hum Mutat, 2018 05;39:593-620). This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). In addition to the clinical data presented in the literature, this alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. As such, this alteration is interpreted as a disease-causing mutation. -
Pathogenic, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Jul 09, 2019	This variant deletes 3 nucleotides and inserts 1 nucleotide in exon 19 of the BRCA2 gene, creating a frameshift and a premature translation stop signal. This variant is expected to result in an absent or non-functional protein product. To our knowledge, functional assays have not been performed for this variant. This variant has been reported in an individual affected with breast cancer, prostate cancer, and gastrointestinal stromal tumor and with a family history of male and female breast cancer (PMID: 26150619). 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. Based on available evidence, this variant is classified as Pathogenic. -

Hereditary breast ovarian cancer syndrome Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Dec 11, 2019	This sequence change deletes 3 nucleotides and inserts 1 nucleotide in exon 19 of the BRCA2 mRNA (c.8414_8416delinsC), causing a frameshift at codon 2805. This creates a premature translational stop signal (p.Leu2805Serfs*6) and is expected to result in an absent or disrupted protein product. This variant is not present in population databases (ExAC no frequency). A set of variants that result in a similar protein effect have been reported in the literature in an individual affected with early-onset breast cancer. In this individual, two variants were described - a frameshift, c.8415_8416delAT (called 8643delAT), and a missense, c.8416T>C (called T8642C). If these two variants are in cis, they would result in the same variant observed here (c.8414_8416delinsC). However, the phase of these variants was not determined in the reported individual (PMID: 12942367). ClinVar contains an entry for this variant (Variation ID: 38159). Loss-of-function variants in BRCA2 are known to be pathogenic (PMID: 20104584). For these reasons, this variant has been classified as Pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Nov 06, 2020	Variant summary: BRCA2 c.8414_8416delinsC (p.Leu2805SerfsX6) 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 326 control chromosomes. c.8414_8416delinsC has been reported in the literature in individuals affected with Hereditary Breast And Ovarian Cancer Syndrome and prostate cancer (example, Rebbeck_2018, Waisbren_2015). To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Six clinical diagnostic laboratories and one expert panel (ENIGMA) 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. -

Familial cancer of breast Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Baylor Genetics

Aug 23, 2022

- -

Computational scores

Source: dbNSFP v4.3

Splicing

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

Publications

LitVar

Other links and lift over

dbSNP: rs397507402; hg19: chr13-32944621;