13-32394803-A-G

Position:

• chr13-32394803-A-G

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1 PM2 PM5 PP3_Moderate

The NM_000059.4(BRCA2):​c.9371A>G​(p.Asn3124Ser) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. N3124I) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 33)
• Consequence: BRCA2 NM_000059.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 6.06

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_pathogenic. Variant got 8 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 4 benign, 15 uncertain in NM_000059.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr13-32394803-A-T is described in ClinVar as [Pathogenic]. Clinvar id is 38233.Status of the report is reviewed_by_expert_panel, 3 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.898

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
BRCA2	NM_000059.4	c.9371A>G	p.Asn3124Ser	missense_variant	25/27	ENST00000380152.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
BRCA2	ENST00000380152.8	c.9371A>G	p.Asn3124Ser	missense_variant	25/27	5	NM_000059.4	A2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251346 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135836

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000880

Gnomad OTH exome AF: 0.00

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Nov 23, 2020

Variant summary: BRCA2 c.9371A>G (p.Asn3124Ser) results in a conservative amino acid change located in the BRCA2, OB3 domain (IPR015188) of the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 4e-06 in 251346 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. To our knowledge, no occurrence of c.9371A>G in individuals affected with Hereditary Breast And Ovarian Cancer Syndrome and no experimental evidence demonstrating its impact on protein function have been reported. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014. Of note, a different nucleotide change, c.9371A>T that results in a different amino acid change at the same codon location (p.Asn3124Ile) has been classified as pathogenic by our laboratory among other submitters, to include an expert panel (ENIGMA), in the ClinVar database. Based on the absence of clinical and functional evidence as outlined above, this variant was classified as uncertain significance. -

Hereditary breast ovarian cancer syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

May 16, 2023

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. This variant disrupts the p.Asn3124 amino acid residue in BRCA2. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 11802209, 20383589, 22678057, 23108138, 24728577, 25085752, 25948282). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. 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) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on BRCA2 protein function. ClinVar contains an entry for this variant (Variation ID: 987839). This variant has not been reported in the literature in individuals affected with BRCA2-related conditions. This variant is present in population databases (rs28897759, gnomAD 0.0009%). This sequence change replaces asparagine, which is neutral and polar, with serine, which is neutral and polar, at codon 3124 of the BRCA2 protein (p.Asn3124Ser). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.27
BayesDel_addAF	Pathogenic	0.16	D
BayesDel_noAF	Uncertain	0.0
CADD	Uncertain	25
DANN	Uncertain	1.0
Eigen	Pathogenic	0.81
Eigen_PC	Pathogenic	0.78
FATHMM_MKL	Uncertain	0.96	D
M_CAP	Pathogenic	0.30	D
MetaRNN	Pathogenic	0.90	D;D
MetaSVM	Pathogenic	0.83	D
MutationTaster	Benign	1.0	D;D
PrimateAI	Benign	0.44	T
PROVEAN	Benign	-1.4	N;N
REVEL	Pathogenic	0.72
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0	D;D
Vest4		0.69
MutPred		0.82		Gain of disorder (P = 0.0407);Gain of disorder (P = 0.0407);
MVP		0.97
MPC		0.16
ClinPred		0.99	D
GERP RS		5.9
gMVP		0.52

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: rs28897759; hg19: chr13-32968940; COSMIC: COSV66455540; COSMIC: COSV66455540;