chr13-32356428-A-G

Position:

• chr13-32356428-A-G

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_000059.4(BRCA2):​c.7436A>G​(p.Asp2479Gly) variant causes a missense, splice region change. The variant allele was found at a frequency of 0.00000137 in 1,460,174 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: BRCA2 NM_000059.4 missense, splice_region
• Scores: Splicing: ADA: 0.04115
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 5.05

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]

BRCA2 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.863

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BRCA2	NM_000059.4	c.7436A>G	p.Asp2479Gly	missense_variant, splice_region_variant	15/27	ENST00000380152.8	NP_000050.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
BRCA2	ENST00000380152.8	c.7436A>G	p.Asp2479Gly	missense_variant, splice_region_variant	15/27	5	NM_000059.4	ENSP00000369497.3
BRCA2	ENST00000530893.7	c.7067A>G	p.Asp2356Gly	missense_variant, splice_region_variant	15/27	1		ENSP00000499438.2
BRCA2	ENST00000614259.2	n.7436A>G		splice_region_variant, non_coding_transcript_exon_variant	14/26	2		ENSP00000506251.1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1460174 Hom.: 0 Cov.: 30 AF XY: 0.00000138 AC XY: 1 AN XY: 726568

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: 9.01e-7

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 31

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Quest Diagnostics Nichols Institute San Juan Capistrano

May 18, 2023

This variant has not been reported in the published literature. It also has not been reported in large, multi-ethnic general populations (Genome Aggregation Database, http://gnomad.broadinstitute.org). Analysis of this variant using bioinformatics tools for the prediction of the effect of amino acid changes on protein structure and function yielded conflicting predictions that this variant is benign or damaging. Based on the available information, we are unable to determine the clinical significance of this variant. -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Oct 18, 2022

The p.D2479G variant (also known as c.7436A>G) is located in coding exon 14 of the BRCA2 gene. The aspartic acid at codon 2479 is replaced by glycine, an amino acid with similar properties. This change occurs in the first base pair of coding exon 14. This amino acid position is highly 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 this alteration remains unclear. -

Hereditary breast ovarian cancer syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Sep 10, 2023

This sequence change replaces aspartic acid, which is acidic and polar, with glycine, which is neutral and non-polar, at codon 2479 of the BRCA2 protein (p.Asp2479Gly). 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: 182239). Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Not Available"; PolyPhen-2: "Benign"; Align-GVGD: "Not Available". The glycine 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	0.11
BayesDel_addAF	Pathogenic	0.24	D
BayesDel_noAF	Uncertain	0.10
CADD	Uncertain	24
DANN	Uncertain	1.0
Eigen	Uncertain	0.35
Eigen_PC	Uncertain	0.36
FATHMM_MKL	Uncertain	0.94	D
M_CAP	Pathogenic	0.30	D
MetaRNN	Pathogenic	0.86	D;D
MetaSVM	Uncertain	0.26	D
PrimateAI	Benign	0.34	T
PROVEAN	Benign	-1.9	N;N
REVEL	Uncertain	0.62
Sift	Uncertain	0.0020	D;D
Sift4G	Uncertain	0.019	D;D
Vest4		0.54
MutPred		0.73		Loss of stability (P = 0.0387);Loss of stability (P = 0.0387);
MVP		0.95
MPC		0.036
ClinPred		0.81	D
GERP RS		5.5
gMVP		0.38

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.041
dbscSNV1_RF	Benign	0.27
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: rs730881555; hg19: chr13-32930565;