NM_000059.4:c.9725C>T

Variant names:

• chr13-32398238-C-T
• rs768210077
• NM_000059.4:c.9725C>T

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_000059.4(BRCA2):​c.9725C>T​(p.Thr3242Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,630 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/20 in silico tools predict a benign 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. T3242P) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: BRCA2 NM_000059.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:6
• Conservation: PhyloP100: -0.207
• Publications: 6 publications found

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 Gene-Disease associations (from GenCC):

• breast-ovarian cancer, familial, susceptibility to, 2

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, Genomics England PanelApp, Labcorp Genetics (formerly Invitae), ClinGen
• Fanconi anemia complementation group D1

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, ClinGen, G2P
• pancreatic cancer, susceptibility to, 2

  Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp
• sarcoma

  Inheritance: AD Classification: MODERATE Submitted by: Genomics England PanelApp
• hereditary breast ovarian cancer syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• Fanconi anemia

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• medulloblastoma

  Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics

ACMG classification

Our verdict: Uncertain_significance. The variant received 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.10836026).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
BRCA2	NM_000059.4	c.9725C>T	p.Thr3242Ile	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.9725C>T	p.Thr3242Ile	missense_variant	Exon 27 of 27	5	NM_000059.4	ENSP00000369497.3
BRCA2	ENST00000530893.7	c.9356C>T	p.Thr3119Ile	missense_variant	Exon 27 of 27	1		ENSP00000499438.2
BRCA2	ENST00000614259.2	n.*1783C>T		non_coding_transcript_exon_variant	Exon 26 of 26	2		ENSP00000506251.1
BRCA2	ENST00000614259.2	n.*1783C>T		3_prime_UTR_variant	Exon 26 of 26	2		ENSP00000506251.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251100 AF XY: 0.00

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 FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000880

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461630 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727120

African (AFR) AF: 0.00 AC: 0 AN: 33446

American (AMR) AF: 0.00 AC: 0 AN: 44686

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26132

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.00 AC: 0 AN: 86204

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53378

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5764

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1111934

Other (OTH) AF: 0.00 AC: 0 AN: 60388

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000756

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:6

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

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

-

Department of Pathology and Laboratory Medicine, Sinai Health System

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

The BRCA2 p.Thr3242Ile variant was not identified in the literature nor was it identified in the LOVD 3.0 and UMD-LSDB databases. The variant was identified in dbSNP (rs768210077) as “with uncertain significance allele” and ClinVar (classified as uncertain significance by Invitae). The variant was identified in control databases in 1 of 251,100 chromosomes at a frequency of 0.000004 (Genome Aggregation Database Feb 27, 2017). The variant was observed in the following populations: European in 1 of 113,586 chromosomes (freq: 0.000009); it was not observed in the African, Latino, Ashkenazi Jewish, East Asian, Finnish, Other and South Asian populations. The p.Thr3242 residue is not conserved in mammals and computational analyses (PolyPhen-2, SIFT, AlignGVGD, BLOSUM, MutationTaster) do not suggest a high likelihood of impact to the protein; however, this information is not predictive enough to rule out pathogenicity. The variant occurs outside of the splicing consensus sequence and in silico or computational prediction software programs (SpliceSiteFinder, MaxEntScan, NNSPLICE, GeneSplicer) do not predict a difference in splicing. In summary, based on the above information the clinical significance of this variant cannot be determined with certainty at this time. This variant is classified as a variant of uncertain significance. -

Oct 30, 2023

All of Us Research Program, National Institutes of Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces threonine with isoleucine at codon 3242 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). To our knowledge, functional studies have not been reported for this variant. This variant has not been reported in individuals affected with hereditary cancer in the literature. This variant has been identified in 1/251100 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 provided Uncertain:2

Oct 01, 2019

Quest Diagnostics Nichols Institute San Juan Capistrano

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jul 18, 2023

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Observed in an individual with bile duct cancer, suspected of having hereditary breast and ovarian cancer syndrome (Lerner-Ellis et al., 2021); In silico analysis supports that this missense variant does not alter protein structure/function; Not observed at significant frequency in large population cohorts (gnomAD); Also known as 9953C>T; This variant is associated with the following publications: (PMID: 32377563, 29884841, 32885271) -

Hereditary cancer-predisposing syndrome Uncertain:1

Jun 04, 2023

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.T3242I variant (also known as c.9725C>T), located in coding exon 26 of the BRCA2 gene, results from a C to T substitution at nucleotide position 9725. The threonine at codon 3242 is replaced by isoleucine, an amino acid with similar properties. This variant was observed in 1/3251 individuals who met eligibility criteria for hereditary breast and ovarian cancer syndrome (Lerner-Ellis J et al. J Cancer Res Clin Oncol, 2021 Mar;147:871-879). This amino acid position is poorly conserved in available vertebrate 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 04, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces threonine, which is neutral and polar, with isoleucine, which is neutral and non-polar, at codon 3242 of the BRCA2 protein (p.Thr3242Ile). This variant is present in population databases (rs768210077, gnomAD 0.0009%). 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: 236933). 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	0.082
BayesDel_addAF	Benign	-0.090	T
BayesDel_noAF	Benign	-0.37
CADD	Benign	9.3
DANN	Benign	0.97
Eigen	Benign	-1.3
Eigen_PC	Benign	-1.3
FATHMM_MKL	Benign	0.048	N
M_CAP	Benign	0.080	D
MetaRNN	Benign	0.11	T;T
MetaSVM	Benign	-0.92	T
PhyloP100		-0.21
PrimateAI	Benign	0.26	T
PROVEAN	Benign	-1.1	N;N
REVEL	Benign	0.21
Sift	Benign	0.16	T;T
Sift4G	Benign	0.14	T;T
Vest4		0.22
MutPred		0.29		Loss of glycosylation at T3242 (P = 0.0058);Loss of glycosylation at T3242 (P = 0.0058);
MVP		0.70
MPC		0.062
ClinPred		0.080	T
GERP RS		-3.7
gMVP		0.36
Mutation Taster		=88/12	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.070		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs768210077; hg19: chr13-32972375;