rs587782691

Positions:

• chr13-32332455-G-A
• chr13-32332455-G-C
• chr13-32332455-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_000059.4(BRCA2):​c.977G>A​(p.Ser326Asn) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000694 in 1,441,092 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/19 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. S326R) has been classified as Benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: BRCA2 NM_000059.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:4 B:1
• Conservation: PhyloP100: 0.181

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 Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.118029416).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BRCA2	NM_000059.4	c.977G>A	p.Ser326Asn	missense_variant	10/27	ENST00000380152.8	NP_000050.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
BRCA2	ENST00000380152.8	c.977G>A	p.Ser326Asn	missense_variant	10/27	5	NM_000059.4	ENSP00000369497	A2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.94e-7 AC: 1 AN: 1441092 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 716222

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: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 9.04e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:4 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Nov 04, 2016	Variant summary: The BRCA2 c.977G>A (p.Ser326Asn) variant causes a missense change involving a non-conserved nucleotide with 4/5 in silico tools predict a benign outcome, although these predictions have yet to be functionally assessed. The variant of interest was not observed in controls (ExAC, 1000 Gs, or ESP), nor has it been, to our knowledge, reported in affected individuals via publications, although multiple databases/clinical diagnostic laboratories have cited the variant with a classification of "uncertain significance." Therefore, until additional information becomes available (ie, clinical and functional studies), the variant of interest has been classified as a "Variant of Uncertain Significance (VUS)." -
Uncertain significance, criteria provided, single submitter	clinical testing	Quest Diagnostics Nichols Institute San Juan Capistrano	Feb 27, 2018	- -

Hereditary cancer-predisposing syndrome Uncertain:1 Benign:1

Likely benign, criteria provided, single submitter	curation	University of Washington Department of Laboratory Medicine, University of Washington	Mar 23, 2023	Missense variant in a coldspot region where missense variants are very unlikely to be pathogenic (PMID:31911673). -
Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Jun 05, 2019	The p.S326N variant (also known as c.977G>A), located in coding exon 9 of the BRCA2 gene, results from a G to A substitution at nucleotide position 977. The serine at codon 326 is replaced by asparagine, an amino acid with highly similar properties. This amino acid position is poorly conserved in available vertebrate species. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Hereditary breast ovarian cancer syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 31, 2024

This sequence change replaces serine, which is neutral and polar, with asparagine, which is neutral and polar, at codon 326 of the BRCA2 protein (p.Ser326Asn). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with BRCA2-related conditions. ClinVar contains an entry for this variant (Variation ID: 142748). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt BRCA2 protein function with a negative predictive value of 95%. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.077
BayesDel_addAF	Benign	-0.18	T
BayesDel_noAF	Benign	-0.50
CADD	Benign	1.1
DANN	Benign	0.26
Eigen	Benign	-1.5
Eigen_PC	Benign	-1.5
FATHMM_MKL	Benign	0.025	N
M_CAP	Benign	0.032	D
MetaRNN	Benign	0.12	T;T
MetaSVM	Benign	-0.91	T
MutationTaster	Benign	1.0	N;N
PrimateAI	Benign	0.30	T
PROVEAN	Benign	-0.30	N;N
REVEL	Benign	0.24
Sift	Benign	0.34	T;T
Sift4G	Benign	0.46	T;T
Vest4		0.17
MutPred		0.27		Loss of phosphorylation at S326 (P = 0.0095);Loss of phosphorylation at S326 (P = 0.0095);
MVP		0.78
MPC		0.039
ClinPred		0.091	T
GERP RS		-3.0
gMVP		0.044

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: rs587782691; hg19: chr13-32906592;