chr13-32316494-T-G

Position:

• chr13-32316494-T-G

Variant summary

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

The ENST00000530893(BRCA2):​c.-332T>G variant causes a 5 prime UTR premature start codon gain change. The variant allele was found at a frequency of 0.0000136 in 1,614,006 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 33)
  • Exomes 𝑓: 0.000014 (0 hom.)
• Consequence: BRCA2 ENST00000530893 5_prime_UTR_premature_start_codon_gain
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:11 B:1
• Conservation: PhyloP100: 4.36

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 0 ACMG points.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BRCA2	NM_000059.4	c.34T>G	p.Phe12Val	missense_variant	2/27	ENST00000380152.8	NP_000050.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
BRCA2	ENST00000530893	c.-332T>G		5_prime_UTR_premature_start_codon_gain_variant	2/27	1		ENSP00000499438.2
BRCA2	ENST00000380152.8	c.34T>G	p.Phe12Val	missense_variant	2/27	5	NM_000059.4	ENSP00000369497.3
BRCA2	ENST00000530893	c.-332T>G		5_prime_UTR_variant	2/27	1		ENSP00000499438.2
BRCA2	ENST00000614259.2	n.34T>G		non_coding_transcript_exon_variant	1/26	2		ENSP00000506251.1

Frequencies

GnomAD3 genomes AF: 0.0000131 AC: 2 AN: 152210 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000147

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000278 AC: 7 AN: 251372 Hom.: 0 AF XY: 0.0000147 AC XY: 2 AN XY: 135878

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: 0.0000462

Gnomad NFE exome AF: 0.0000528

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000137 AC: 20 AN: 1461796 Hom.: 0 Cov.: 32 AF XY: 0.0000110 AC XY: 8 AN XY: 727200

Gnomad4 AFR exome AF: 0.0000299

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: 0.0000374

Gnomad4 NFE exome AF: 0.0000117

Gnomad4 OTH exome AF: 0.0000662

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152210 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 74370

Gnomad4 AFR AF: 0.0000241

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000147

Gnomad4 OTH AF: 0.00

Bravo AF: 0.00000756

ExAC AF: 0.0000412 AC: 5

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:11 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Breast-ovarian cancer, familial, susceptibility to, 2 Uncertain:4

Uncertain significance, no assertion criteria provided	clinical testing	Sharing Clinical Reports Project (SCRP)	May 21, 2012	- -
Uncertain significance, no assertion criteria provided	clinical testing	BRCAlab, Lund University	Mar 02, 2020	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Counsyl	May 01, 2017	- -
Uncertain significance, no assertion criteria provided	clinical testing	Breast Cancer Information Core (BIC) (BRCA2)	Jan 17, 2001	- -

not provided Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Feb 09, 2023	Published functional studies demonstrate DNA double-strand break repair ability, PALB2 binding, and cellular localization similar to wild type (Xia et al., 2006); In silico analysis supports that this missense variant does not alter protein structure/function; Observed in an individual with endometrial cancer (Huang et al., 2018); Also known as 262T>G; This variant is associated with the following publications: (PMID: 24323938, 31131967, 16793542, 29625052) -
Uncertain significance, criteria provided, single submitter	clinical testing	Quest Diagnostics Nichols Institute San Juan Capistrano	Nov 03, 2018	- -

Hereditary cancer-predisposing syndrome Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Feb 16, 2024	The p.F12V variant (also known as c.34T>G), located in coding exon 1 of the BRCA2 gene, results from a T to G substitution at nucleotide position 34. The phenylalanine at codon 12 is replaced by valine, an amino acid with highly similar properties. A functional assay demonstrated that this variant falls within the PALB2 binding motif and retained normal PALB2 binding activity (Xia et al. Mol Cell. 2006 Jun 23;22(6):719-29). In addition, a homology directed repair assay demonstrated that homology directed repair activity for this alteration is similar to wildtype (Guidugli L et al. Hum. Mutat., 2014 Feb;35:151-64). This amino acid position is well conserved in available vertebrate species. In addition, this alteration is predicted to be tolerated by in silico analysis. Based on the available evidence, the clinical significance of this alteration remains unclear. -
Uncertain significance, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Jul 25, 2022	This missense variant replaces phenylalanine with valine at codon 12 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). Functional studies have shown that this variant has no impact on homology-directed DNA repair function (PMID: 16793542). In a large breast cancer case-control study conducted by the BRIDGES consortium, this variant was reported in 6/60466 cases, 1/53461 controls; p-value=0.13; Leiden Open Variation Database DB-ID BRCA2_007668 (PMID: 33471991). This variant has been identified in 7/251372 chromosomes 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. -

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

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

Oct 03, 2022

Variant summary: BRCA2 c.34T>G (p.Phe12Val) results in a non-conservative amino acid change in the encoded protein sequence. Two of four in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 2.8e-05 in 251372 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.34T>G has been reported in the literature in an individual affected with Uterine Corpus Endometrial Carcinoma (Huang_2018) without evidence of causality. This report does not provide unequivocal conclusions about association of the variant with Hereditary Breast And Ovarian Cancer Syndrome. One publication reports experimental evidence evaluating an impact on protein function (Xia_2006), showing no damaging effect of this variant. Six clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. Based on the evidence outlined above, the variant was classified as uncertain significance. -

BRCA2-related cancer predisposition Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

All of Us Research Program, National Institutes of Health

Sep 23, 2024

This missense variant replaces phenylalanine with valine at codon 12 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). Functional studies have shown that this variant has no impact on homology-directed DNA repair function (PMID: 16793542). In a large breast cancer case-control study conducted by the BRIDGES consortium, this variant was reported in 6/60466 cases, 1/53461 controls; p-value=0.13; Leiden Open Variation Database DB-ID BRCA2_007668 (PMID: 33471991). This variant has been identified in 7/251372 chromosomes 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. -

Familial cancer of breast Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Baylor Genetics

Mar 29, 2024

- -

Hereditary breast ovarian cancer syndrome Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Dec 07, 2023

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.33
BayesDel_addAF	Benign	-0.14	T
BayesDel_noAF	Benign	-0.30
CADD	Uncertain	26
DANN	Uncertain	0.99
Eigen	Uncertain	0.61
Eigen_PC	Uncertain	0.60
FATHMM_MKL	Uncertain	0.88	D
M_CAP	Uncertain	0.096	D
MetaRNN	Uncertain	0.45	T;T
MetaSVM	Benign	-1.2	T
PrimateAI	Uncertain	0.55	T
PROVEAN	Benign	-1.6	N;N
REVEL	Benign	0.11
Sift	Uncertain	0.0010	D;D
Sift4G	Uncertain	0.0050	D;D
Vest4		0.51
MutPred		0.40		Loss of catalytic residue at F12 (P = 0.0348);Loss of catalytic residue at F12 (P = 0.0348);
MVP		0.91
MPC		0.044
ClinPred		0.47	T
GERP RS		5.3
gMVP		0.63

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: rs80358597; hg19: chr13-32890631;