rs1555284478

Positions:

• chr13-32340302-G-A
• chr13-32340302-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 3P and 1B. PM2 PP3 BP6

The NM_000059.4(BRCA2):​c.5947G>A​(p.Gly1983Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 11/19 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. G1983G) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 33)
• Consequence: BRCA2 NM_000059.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2 B:1
• Conservation: PhyloP100: 7.78

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 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.783
• BP6: Variant 13-32340302-G-A is Benign according to our data. Variant chr13-32340302-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 433797.We mark this variant Likely_benign, oryginal submissions are: {Uncertain_significance=1, Likely_benign=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
BRCA2	NM_000059.4	c.5947G>A	p.Gly1983Arg	missense_variant	11/27	ENST00000380152.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
BRCA2	ENST00000380152.8	c.5947G>A	p.Gly1983Arg	missense_variant	11/27	5	NM_000059.4	A2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 46

GnomAD4 genome Cov.: 33

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:2 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Malignant tumor of breast Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

Department of Pathology and Laboratory Medicine, Sinai Health System

-

The BRCA2 p.Gly1983Arg variant was not identified in the literature nor was it identified in the dbSNP, NHLBI Exome Sequencing Project (Exome Variant Server), HGMD, LOVD, COSMIC, UMD, ClinVar, or BIC databases. The p.Gly1983 residue is conserved across mammals and lower organisms, and computational analyses (PolyPhen-2, SIFT, AlignGVGD, BLOSUM, MutationTaster) suggest that the p.Gly1983Arg variant may impact the protein. However, this information is not predictive enough to assume pathogenicity. In summary, based on the above information, the clinical significance of this variant cannot be determined with certainty at this time. This variant is classified as a variant of unknown significance. -

Hereditary breast ovarian cancer syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Aug 02, 2018

This sequence change replaces glycine with arginine at codon 1983 of the BRCA2 protein (p.Gly1983Arg). The glycine residue is highly conserved and there is a moderate physicochemical difference between glycine and arginine. This variant is not present in population databases (ExAC no frequency). 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. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has not been reported in the literature in individuals with BRCA2-related disease. ClinVar contains an entry for this variant (Variation ID: 433797). -

Hereditary cancer-predisposing syndrome 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). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.58
BayesDel_addAF	Pathogenic	0.32	D
BayesDel_noAF	Pathogenic	0.22
CADD	Pathogenic	27
DANN	Pathogenic	1.0
Eigen	Pathogenic	0.89
Eigen_PC	Pathogenic	0.87
FATHMM_MKL	Pathogenic	0.99	D
M_CAP	Pathogenic	0.44	D
MetaRNN	Pathogenic	0.78	D;D
MetaSVM	Uncertain	0.62	D
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.58	T
PROVEAN	Pathogenic	-7.8	D;D
REVEL	Pathogenic	0.81
Sift	Uncertain	0.0010	D;D
Sift4G	Uncertain	0.0050	D;D
Vest4		0.53
MutPred		0.65		Gain of MoRF binding (P = 0.0348);Gain of MoRF binding (P = 0.0348);
MVP		0.97
MPC		0.17
ClinPred		1.0	D
GERP RS		5.7
gMVP		0.54

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: rs1555284478; hg19: chr13-32914439;