chr13-32362527-CTG-C

Position:

• chr13-32362527-CTG-C

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.7815_7816del​(p.Cys2605Ter) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,344 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: BRCA2 NM_000059.4 frameshift
• Clinical Significance: Pathogenic reviewed by expert panel P:6
• Conservation: PhyloP100: 7.90

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 13-32362527-CTG-C is Pathogenic according to our data. Variant chr13-32362527-CTG-C is described in ClinVar as [Pathogenic]. Clinvar id is 267037.Status of the report is reviewed_by_expert_panel, 3 stars. Variant chr13-32362527-CTG-C is described in Lovd as [Pathogenic]. Variant chr13-32362527-CTG-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BRCA2	NM_000059.4	c.7815_7816del	p.Cys2605Ter	frameshift_variant	17/27	ENST00000380152.8	NP_000050.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
BRCA2	ENST00000380152.8	c.7815_7816del	p.Cys2605Ter	frameshift_variant	17/27	5	NM_000059.4	ENSP00000369497	A2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461344 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 727018

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000224

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:6

Revision: reviewed by expert panel

Submissions by phenotype

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

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)	Oct 18, 2016	Variant allele predicted to encode a truncated non-functional protein. -

Hereditary cancer-predisposing syndrome Pathogenic:2

Pathogenic, criteria provided, single submitter	curation	Sema4, Sema4	Feb 03, 2021	- -
Pathogenic, criteria provided, single submitter	clinical testing	Ambry Genetics	Sep 17, 2020	The c.7815_7816delTG pathogenic mutation, located in coding exon 16 of the BRCA2 gene, results from a deletion of two nucleotides at nucleotide positions 7815 to 7816, causing a translational frameshift with a predicted alternate stop codon (p.C2605*). This mutation was identified in a Spanish individual that was part of a large, worldwide study of BRCA1/2 mutation positive families (Rebbeck TR et al. Hum. Mutat., 2018 05;39:593-620). Another BRCA2 alteration, c.7815T>A, that leads to the same premature stop codon (p.C2605*), was identified in 2/2991 Chinese breast cancer patients and was not detected in 1043 healthy controls (Lang GT et al. Int. J. Cancer, 2017 07;141:129-142). 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. -

not provided Pathogenic:1

Pathogenic, no assertion criteria provided

clinical testing

Department of Pathology and Laboratory Medicine, Sinai Health System

-

The p.Cys2605X variant has not been reported in the literature. The variant leads to a premature stop codon at position 2605 which is predicted to cause premature truncation of the protein product and loss of function. Loss of function variants in the BRCA2 gene is an established disease mechanism in hereditary breast and ovarian cancer. In summary, based on the above information, this variant is classified as pathogenic. -

Hereditary breast ovarian cancer syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Aug 09, 2021

For these reasons, this variant has been classified as Pathogenic. Loss-of-function variants in BRCA2 are known to be pathogenic (PMID: 20104584). This variant has been reported in individuals in the Leiden Open-source Variation Database (PMID: 21520333). ClinVar contains an entry for this variant (Variation ID: 267037). This variant is not present in population databases (ExAC no frequency). This sequence change creates a premature translational stop signal (p.Cys2605*) in the BRCA2 gene. It is expected to result in an absent or disrupted protein product. -

Computational scores

Source: dbNSFP v4.3

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: rs886040730; hg19: chr13-32936664;