13-32340342-C-G

Position:

• chr13-32340342-C-G

Variant summary

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

The NM_000059.4(BRCA2):​c.5987C>G​(p.Ala1996Gly) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. 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. A1996I) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 33)
• Consequence: BRCA2 NM_000059.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:4 B:2
• Conservation: PhyloP100: 6.20

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 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP6: Variant 13-32340342-C-G is Benign according to our data. Variant chr13-32340342-C-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 187639.We mark this variant Likely_benign, oryginal submissions are: {Uncertain_significance=4, Likely_benign=2}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
BRCA2	NM_000059.4	c.5987C>G	p.Ala1996Gly	missense_variant	11/27	ENST00000380152.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
BRCA2	ENST00000380152.8	c.5987C>G	p.Ala1996Gly	missense_variant	11/27	5	NM_000059.4	A2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 44

GnomAD4 genome Cov.: 33

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:4 Benign:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:2 Benign:1

Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Dec 23, 2014	The p.A1996G variant (also known as c.5987C>G and 6215C>G), located in coding exon 10 of the BRCA2 gene, results from a C to G substitution at nucleotide position 5987. The alanine at codon 1996 is replaced by glycine, an amino acid with similar properties. This alteration was detected in a familial breast and/or ovarian cancer patient; a cDNA-based test showed that the patient had a BRCA2 out-of-frame transcript lacking exons 12 and 13. Subsequent genomic analysis showed a genomic deletion encompassing exons 12 and 13 (Caux-Moncoutier V, Eur. J. Hum. Genet. 2009 Nov; 17(11):1471-80). 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 6500 samples (13000 alleles) with coverage at this position. To date, this alteration has been detected with an allele frequency of approximately 0.001% (greater than 105000 alleles tested) in our clinical cohort. This amino acid position is well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of p.A1996G 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). -
Uncertain significance, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Jan 08, 2024	This missense variant replaces alanine with glycine at codon 1996 of the BRCA2 protein. Computational prediction is inconclusive regarding the impact of this variant on protein structure and function (internally defined REVEL score threshold 0.5 < inconclusive < 0.7, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in 1 individual affected with breast cancer, this individual also carried a pathogenic CNV in BRCA2 that could explain the observed phenotype (PMID: 19471317). 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 and/or ovarian cancer Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario

Feb 23, 2022

- -

Hereditary breast ovarian cancer syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Dec 28, 2023

This sequence change replaces alanine, which is neutral and non-polar, with glycine, which is neutral and non-polar, at codon 1996 of the BRCA2 protein (p.Ala1996Gly). RNA analysis indicates that this missense change induces altered splicing and may result in an absent or disrupted protein product. This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with breast and/or ovarian cancer (PMID: 19471317). ClinVar contains an entry for this variant (Variation ID: 187639). 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%. Studies have shown that this missense change results in skipping of exons 11 and 12 (also known as exons 12 and 13) and introduces a premature termination codon (PMID: 19471317). The resulting mRNA is expected to undergo nonsense-mediated decay. 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. -

Familial cancer of breast Benign:1

Likely benign, criteria provided, single submitter

clinical testing

MGZ Medical Genetics Center

Feb 09, 2024

ACMG codes applied following ENIGMA VCEP rules: BP1_STR, PM2_SUP -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.27
BayesDel_addAF	Pathogenic	0.21	D
BayesDel_noAF	Uncertain	0.060
CADD	Uncertain	25
DANN	Uncertain	1.0
Eigen	Pathogenic	0.83
Eigen_PC	Pathogenic	0.81
FATHMM_MKL	Pathogenic	0.98	D
M_CAP	Uncertain	0.23	D
MetaRNN	Uncertain	0.59	D;D
MetaSVM	Uncertain	0.51	D
MutationTaster	Benign	1.0	D;D
PrimateAI	Benign	0.39	T
PROVEAN	Uncertain	-3.8	D;D
REVEL	Uncertain	0.64
Sift	Uncertain	0.0020	D;D
Sift4G	Uncertain	0.012	D;D
Vest4		0.55
MutPred		0.51		Loss of helix (P = 0.0167);Loss of helix (P = 0.0167);
MVP		0.93
MPC		0.16
ClinPred		0.98	D
GERP RS		5.7
gMVP		0.38

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: rs80358834; hg19: chr13-32914479; COSMIC: COSV66458686;