13-32362600-T-C

Position:

• chr13-32362600-T-C

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 4P and 1B. PM2 PP3_Moderate BP6

The NM_000059.4(BRCA2):​c.7883T>C​(p.Ile2628Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,864 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: BRCA2 NM_000059.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:5 B:2
• Conservation: PhyloP100: 7.93

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 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.889
• BP6: Variant 13-32362600-T-C is Benign according to our data. Variant chr13-32362600-T-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 252849.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=2, Uncertain_significance=4}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BRCA2	NM_000059.4	c.7883T>C	p.Ile2628Thr	missense_variant	17/27	ENST00000380152.8	NP_000050.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
BRCA2	ENST00000380152.8	c.7883T>C	p.Ile2628Thr	missense_variant	17/27	5	NM_000059.4	ENSP00000369497.3
BRCA2	ENST00000530893.7	c.7514T>C	p.Ile2505Thr	missense_variant	17/27	1		ENSP00000499438.2
BRCA2	ENST00000614259.2	n.7891T>C		non_coding_transcript_exon_variant	16/26	2		ENSP00000506251.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461864 Hom.: 0 Cov.: 33 AF XY: 0.00000138 AC XY: 1 AN XY: 727228

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: 0.00000270

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000756

Asia WGS AF: 0.000289 AC: 1 AN: 3478

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:5 Benign:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	May 03, 2016	This variant is denoted BRCA2 c.7883T>C at the cDNA level, p.Ile2628Thr (I2628T) at the protein level, and results in the change of an Isoleucine to a Threonine (ATA>ACA). Using alternate nomenclature, this variant would be defined as BRCA2 8111T>C. This variant has not, to our knowledge, been published in the literature as pathogenic or benign. BRCA2 Ile2628Thr was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, suggesting it is not a common benign variant in these populations. Since Isoleucine and Threonine differ in polarity, charge, size or other properties, this is considered a non-conservative amino acid substitution. BRCA2 Ile2628Thr occurs at a position where amino acids with properties similar to Isoleucine are tolerated across species and is located in the DNA binding domain as well as a region known to interact with SHFM1 (Marston 1999, Yang 2002) . In silico analyses predict that this variant is probably damaging to protein structure and function. Based on currently available evidence, it is unclear whether BRCA2 Ile2628Thr is a pathogenic or benign variant. We consider it to be a variant of uncertain significance. -
Uncertain significance, criteria provided, single submitter	clinical testing	Quest Diagnostics Nichols Institute San Juan Capistrano	Nov 08, 2024	The BRCA2 c.7883T>C (p.Ile2628Thr) variant has been reported in the published literature in an individual with breast cancer in a large scale breast cancer association study (PMID: 33471991 (2021), see also LOVD (http://databases.lovd.nl/shared)), and described to be located in a region of the BRCA2 gene that is tolerant to missense sequence changes (PMID: 31911673 (2020)). This variant 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. -

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

Uncertain significance, no assertion criteria provided	clinical testing	Sharing Clinical Reports Project (SCRP)	Jan 08, 2014	- -
Likely benign, criteria provided, single submitter	clinical testing	Myriad Genetics, Inc.	Feb 07, 2024	This variant is considered likely benign. This variant is strongly associated with less severe personal and family histories of cancer, typical for individuals without pathogenic variants in this gene [PMID: 25085752]. -

Hereditary cancer-predisposing syndrome Uncertain:1 Benign:1

Uncertain significance, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Nov 13, 2023	This missense variant replaces isoleucine with threonine at codon 2628 of the BRCA2 protein. Computational prediction is inconclusive regarding the impact of this variant on protein structure and function (internally defined REVEL score threshold 0.5 < inconclusive < 0.7, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in an individual affected with breast cancer (PMID: 33471991; Leiden Open Variation Database DB-ID BRCA2_008630) and in a multifactorial analysis with segregation and tumor pathology likelihood ratios for pathogenicity of 1.8088 and 1.1236, respectively (PMID: 31131967). This variant has not been identified 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. -
Likely benign, criteria provided, single submitter	clinical testing	Ambry Genetics	Jan 05, 2022	This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Hereditary breast ovarian cancer syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

May 08, 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. 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) performed at Invitae indicates that this missense variant is not expected to disrupt BRCA2 protein function. ClinVar contains an entry for this variant (Variation ID: 252849). This variant has not been reported in the literature in individuals affected with BRCA2-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces isoleucine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 2628 of the BRCA2 protein (p.Ile2628Thr). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.45
BayesDel_addAF	Pathogenic	0.37	D
BayesDel_noAF	Pathogenic	0.30
CADD	Uncertain	25
DANN	Uncertain	1.0
Eigen	Pathogenic	0.73
Eigen_PC	Pathogenic	0.74
FATHMM_MKL	Uncertain	0.95	D
M_CAP	Uncertain	0.20	D
MetaRNN	Pathogenic	0.89	D;D
MetaSVM	Uncertain	0.71	D
PrimateAI	Uncertain	0.52	T
PROVEAN	Benign	-1.2	N;N
REVEL	Pathogenic	0.69
Sift	Uncertain	0.0010	D;D
Sift4G	Uncertain	0.0050	D;D
Vest4		0.84
MutPred		0.62		Loss of stability (P = 0.013);Loss of stability (P = 0.013);
MVP		0.99
MPC		0.15
ClinPred		0.97	D
GERP RS		5.7
gMVP		0.47

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs879255465; hg19: chr13-32936737;