13-32340032-T-G

Variant names:

• chr13-32340032-T-G
• rs786203261
• NM_000059.4:c.5677T>G

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM5 BP4_Moderate

The NM_000059.4(BRCA2):​c.5677T>G​(p.Cys1893Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000753 in 1,461,296 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. C1893?) has been classified as Pathogenic.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000075 (0 hom.)
• Consequence: BRCA2 NM_000059.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:5 B:2
• Conservation: PhyloP100: 0.0730

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.

• PM5: Other missense variant is known to change same aminoacid residue: Variant chr13-32340031-TTG-TA is described in Lovd as [Pathogenic].
• BP4: Computational evidence support a benign effect (MetaRNN=0.12124455).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
BRCA2	NM_000059.4	c.5677T>G	p.Cys1893Gly	missense_variant	Exon 11 of 27	ENST00000380152.8	NP_000050.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
BRCA2	ENST00000380152.8	c.5677T>G	p.Cys1893Gly	missense_variant	Exon 11 of 27	5	NM_000059.4	ENSP00000369497.3
BRCA2	ENST00000530893.7	c.5308T>G	p.Cys1770Gly	missense_variant	Exon 11 of 27	1		ENSP00000499438.2
BRCA2	ENST00000614259.2	n.5677T>G		non_coding_transcript_exon_variant	Exon 10 of 26	2		ENSP00000506251.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000753 AC: 11 AN: 1461296 Hom.: 0 Cov.: 47 AF XY: 0.00000963 AC XY: 7 AN XY: 726928

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: 0.00000989

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:5 Benign:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:2 Benign:1

Oct 13, 2023

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.C1893G variant (also known as c.5677T>G), located in coding exon 10 of the BRCA2 gene, results from a T to G substitution at nucleotide position 5677. The cysteine at codon 1893 is replaced by glycine, an amino acid with highly dissimilar 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. -

Mar 23, 2023

University of Washington Department of Laboratory Medicine, University of Washington

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: curation

Missense variant in a coldspot region where missense variants are very unlikely to be pathogenic (PMID:31911673). -

Nov 09, 2023

Color Diagnostics, LLC DBA Color Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces cysteine with glycine at codon 1893 of the BRCA2 protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in a multifactorial analysis with co-occurrence and family history likelihood ratios for pathogenicity of 1.025 and 0.935, respectively (PMID: 31131967). This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -

Breast-ovarian cancer, familial, susceptibility to, 2 Uncertain:1 Benign:1

Dec 13, 2023

All of Us Research Program, National Institutes of Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces cysteine with glycine at codon 1893 of the BRCA2 protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in a multifactorial analysis with co-occurrence and family history likelihood ratios for pathogenicity of 1.025 and 0.935, respectively (PMID: 31131967). This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -

Sep 01, 2023

Department of Medical and Surgical Sciences, University of Bologna

Significance: Likely benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

PM2(Supporting)+BP1(Strong) according to ACMG/AMP classification guidelines specified for BRCA1 & BRCA2 (Classification Criteria V1.0.0 2023-09-08 - https://cspec.genome.network/cspec/ui/svi/affiliation/50087) (PMID: 38160042) -

not provided Uncertain:1

-

Department of Pathology and Laboratory Medicine, Sinai Health System

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

The p.Cys1893Gly variant was not identified in the literature, nor was it identified in the dbSNP, NHLBI Exome Sequencing Project (Exome Variant Server), Exome Aggregation Consortium (ExAC), HGMD, LOVD, COSMIC, ClinVar, GeneInsight VariantWire, BIC, UMD, Breast Cancer IARC or LOVD IARC databases. The variant was found in the canSAR cell line database from the United Kingdom. The Cys1893 residue is not conserved in mammals and four out of five computational analyses (PolyPhen-2, SIFT, AlignGVGD, BLOSUM, MutationTaster) do not suggest a high likelihood of impact to the protein. However, this information is not predictive enough to rule out pathogenicity. The p.Cys1893Gly variant occurs outside of the splicing consensus sequence and 1 of 5 in silico or computational prediction software programs (SpliceSiteFinder, MaxEntScan, NNSPLICE, GeneSplicer, HumanSpliceFinder) predict a greater than 10% difference in splicing; this is not very predictive of 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

Jul 28, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces cysteine, which is neutral and slightly polar, with glycine, which is neutral and non-polar, at codon 1893 of the BRCA2 protein (p.Cys1893Gly). 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: 186838). 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	0.090
BayesDel_addAF	Benign	-0.063	T
BayesDel_noAF	Benign	-0.33
CADD	Benign	2.1
DANN	Benign	0.46
Eigen	Benign	-1.3
Eigen_PC	Benign	-1.4
FATHMM_MKL	Benign	0.11	N
M_CAP	Benign	0.055	D
MetaRNN	Benign	0.12	T;T
MetaSVM	Benign	-1.0	T
PrimateAI	Benign	0.22	T
PROVEAN	Uncertain	-2.4	N;N
REVEL	Benign	0.25
Sift	Benign	0.29	T;T
Sift4G	Benign	0.33	T;T
Vest4		0.32
MutPred		0.42		Gain of loop (P = 0.0079);Gain of loop (P = 0.0079);
MVP		0.53
MPC		0.026
ClinPred		0.15	T
GERP RS		-1.1
gMVP		0.16

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: rs786203261; hg19: chr13-32914169;