rs776353983

Positions:

• chr13-32370548-C-A
• chr13-32370548-C-G
• chr13-32370548-C-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.8478C>A​(p.Tyr2826Ter) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,460,158 control chromosomes in the GnomAD database, with no homozygous occurrence. 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: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: BRCA2 NM_000059.4 stop_gained
• Clinical Significance: Pathogenic reviewed by expert panel P:7
• Conservation: PhyloP100: 0.0720

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 13-32370548-C-A is Pathogenic according to our data. Variant chr13-32370548-C-A is described in ClinVar as [Pathogenic]. Clinvar id is 254623.Status of the report is reviewed_by_expert_panel, 3 stars. Variant chr13-32370548-C-A is described in Lovd as [Pathogenic]. Variant chr13-32370548-C-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BRCA2	NM_000059.4	c.8478C>A	p.Tyr2826Ter	stop_gained	19/27	ENST00000380152.8	NP_000050.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
BRCA2	ENST00000380152.8	c.8478C>A	p.Tyr2826Ter	stop_gained	19/27	5	NM_000059.4	ENSP00000369497	A2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251318 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135842

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.0000327

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1460158 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 726556

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:7

Revision: reviewed by expert panel

Submissions by phenotype

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

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. -
Likely pathogenic, criteria provided, single submitter	clinical testing	Counsyl	Nov 08, 2016	- -

not provided Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Quest Diagnostics Nichols Institute San Juan Capistrano	Mar 18, 2020	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 patient with expected phenotype for this gene, and found in general population data at a frequency that is consistent with pathogenicity. -
Pathogenic, no assertion criteria provided	clinical testing	Department of Pathology and Laboratory Medicine, Sinai Health System	-	The BRCA2 p.Tyr2826X variant was not identified in the literature, nor was it identified in several database searches (dbSNP, NHLBI Exome Sequencing Project, HGMD, LOVD, COSMIC, ClinVar, GeneInsight COGR, BIC, UMD). The variant was identified in the Exome Aggregation Consortium (ExAC) database in 1 of 16542 chromosomes from a South Asian population. The p.Tyr2826X variant leads to a premature stop codon at position 2826, which is predicted to lead to a truncated or absent protein and loss of function. Loss of function variants of the BRCA2 gene are an established mechanism of disease in hereditary breast and ovarian cancer and is the type of variant expected to cause the disorder. In summary, based on the above information, this variant meets our laboratory’s criteria to be classified as pathogenic. -

Familial cancer of breast Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Baylor Genetics

Jul 24, 2023

- -

Hereditary cancer-predisposing syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Apr 29, 2024

The p.Y2826* pathogenic mutation (also known as c.8478C>A), located in coding exon 18 of the BRCA2 gene, results from a C to A substitution at nucleotide position 8478. This changes the amino acid from a tyrosine to a stop codon within coding exon 18. This variant was reported in multiple individuals with features consistent with BRCA2-related hereditary breast and ovarian cancer syndrome (Santonocito C et al. Cancers (Basel), 2020 May;12; Bisgin A et al. Breast, 2022 Oct;65:15-22; Yao L et al. J Hum Genet, 2022 Nov;67:639-642). 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. -

Hereditary breast ovarian cancer syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 24, 2023

This sequence change creates a premature translational stop signal (p.Tyr2826*) in the BRCA2 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in BRCA2 are known to be pathogenic (PMID: 20104584). This variant is present in population databases (rs776353983, gnomAD 0.003%). This premature translational stop signal has been observed in individual(s) with breast cancer and/or ovarian cancer (PMID: 28724667, 32438681). ClinVar contains an entry for this variant (Variation ID: 254623). For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.57	D
BayesDel_noAF	Pathogenic	0.58
CADD	Pathogenic	37
DANN	Uncertain	0.99
Eigen	Uncertain	0.30
Eigen_PC	Benign	0.12
FATHMM_MKL	Uncertain	0.88	D
MutationTaster	Benign	1.0	A;A
Vest4		0.95
GERP RS		2.1

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs776353983; hg19: chr13-32944685;