rs786202940

chr13-32332881-G-Achr13-32332881-G-C

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 2P and 5B. PM2 BP4_Strong BP6

The NM_000059.4(BRCA2):c.1403G>A(p.Arg468Lys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000343 in 1,458,922 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/19 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. R468T) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000034 (0 hom.)
• Consequence: BRCA2 NM_000059.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2 B:1
• Conservation: PhyloP100: -0.545

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 Likely_benign. Variant got -3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.05577293).
• BP6: Variant 13-32332881-G-A is Benign according to our data. Variant chr13-32332881-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 186423.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=1, Uncertain_significance=2}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
BRCA2	NM_000059.4	c.1403G>A	p.Arg468Lys	missense_variant	10/27	ENST00000380152.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
BRCA2	ENST00000380152.8	c.1403G>A	p.Arg468Lys	missense_variant	10/27	5	NM_000059.4	A2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000343 AC: 5 AN: 1458922 Hom.: 0 Cov.: 35 AF XY: 0.00000551 AC XY: 4 AN XY: 725568

Gnomad4 AFR exome AF: 0.0000601

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: 0.00000270

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:2 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:1 Benign:1

Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Oct 07, 2014	The p.R468K variant (also known as c.1403G>A and 1631G>A), located in coding exon 9 of the BRCA2 gene, results from a G to A substitution at nucleotide position 1403. The arginine at codon 468 is replaced by lysine, an amino acid with highly similar properties. This variant was not reported in population based cohorts in the following databases: Database of Single Nucleotide Polymorphisms (dbSNP), NHLBI Exome Sequencing Project (ESP), and 1000 Genomes Project. In the ESP, this variant was not observed in 6503 samples (13006 alleles) with coverage at this position. To date, this alteration has been detected with an allele frequency of approximately 0.002% (greater than 64000 alleles tested) in our clinical cohort. This amino acid position is not well 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 p.R468K remains unclear. -
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). -

Hereditary breast ovarian cancer syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Sep 01, 2021

This sequence change replaces arginine with lysine at codon 468 of the BRCA2 protein (p.Arg468Lys). The arginine residue is weakly conserved and there is a small physicochemical difference between arginine and lysine. This variant is not present in population databases (ExAC 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: 186423). Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The lysine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. 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	0.088
BayesDel_addAF	Benign	-0.22	T
BayesDel_noAF	Benign	-0.55
Cadd	Benign	0.027
Dann	Benign	0.50
Eigen	Benign	-1.4
Eigen_PC	Benign	-1.4
FATHMM_MKL	Benign	0.029	N
M_CAP	Benign	0.061	D
MetaRNN	Benign	0.056	T;T
MetaSVM	Benign	-0.94	T
MutationTaster	Benign	1.0	N;N
PrimateAI	Benign	0.18	T
PROVEAN	Benign	-0.39	N;N
REVEL	Uncertain	0.39
Sift	Benign	0.58	T;T
Sift4G	Benign	0.89	T;T
Vest4		0.12
MutPred		0.25		Gain of ubiquitination at R468 (P = 0);Gain of ubiquitination at R468 (P = 0);
MVP		0.72
MPC		0.021
ClinPred		0.024	T
GERP RS		-2.2
gMVP		0.12

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: rs786202940; hg19: chr13-32907018;