13-32398289-T-C

Variant names:

• chr13-32398289-T-C
• rs879255305
• NM_000059.4:c.9776T>C

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_000059.4(BRCA2):​c.9776T>C​(p.Ile3259Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 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 Uncertain significance (★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: BRCA2 NM_000059.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: -0.380

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_benign. Variant got -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.04288441).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
BRCA2	NM_000059.4	c.9776T>C	p.Ile3259Thr	missense_variant	Exon 27 of 27	ENST00000380152.8	NP_000050.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
BRCA2	ENST00000380152.8	c.9776T>C	p.Ile3259Thr	missense_variant	Exon 27 of 27	5	NM_000059.4	ENSP00000369497.3
BRCA2	ENST00000530893.7	c.9407T>C	p.Ile3136Thr	missense_variant	Exon 27 of 27	1		ENSP00000499438.2
BRCA2	ENST00000614259.2	n.*1834T>C		non_coding_transcript_exon_variant	Exon 26 of 26	2		ENSP00000506251.1
BRCA2	ENST00000614259.2	n.*1834T>C		3_prime_UTR_variant	Exon 26 of 26	2		ENSP00000506251.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

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

Mar 26, 2016

Quest Diagnostics Nichols Institute San Juan Capistrano

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Hereditary cancer-predisposing syndrome Uncertain:1

Mar 20, 2023

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.I3259T variant (also known as c.9776T>C), located in coding exon 26 of the BRCA2 gene, results from a T to C substitution at nucleotide position 9776. The isoleucine at codon 3259 is replaced by threonine, an amino acid with similar properties. This amino acid position is not conserved however, threonine is a reference amino acid in several 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. -

Hereditary breast ovarian cancer syndrome Uncertain:1

Dec 18, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces isoleucine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 3259 of the BRCA2 protein (p.Ile3259Thr). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with clinical features of BRCA2-related conditions (PMID: 21520333). ClinVar contains an entry for this variant (Variation ID: 252418). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) 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	0.048
BayesDel_addAF	Benign	-0.20	T
BayesDel_noAF	Benign	-0.52
CADD	Benign	3.6
DANN	Benign	0.83
Eigen	Benign	-0.97
Eigen_PC	Benign	-0.94
FATHMM_MKL	Benign	0.046	N
M_CAP	Benign	0.022	T
MetaRNN	Benign	0.043	T;T
MetaSVM	Benign	-0.91	T
PrimateAI	Benign	0.32	T
PROVEAN	Benign	-0.67	N;N
REVEL	Benign	0.12
Sift	Benign	0.31	T;T
Sift4G	Benign	0.33	T;T
Vest4		0.050
MutPred		0.12		Loss of stability (P = 0.0164);Loss of stability (P = 0.0164);
MVP		0.56
MPC		0.022
ClinPred		0.026	T
GERP RS		-0.36
gMVP		0.11

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs879255305; hg19: chr13-32972426;