13-32338692-T-C

Position:

• chr13-32338692-T-C

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 2P and 3B. PM2 BP4_Moderate BP6

The NM_000059.4(BRCA2):​c.4337T>C​(p.Ile1446Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000695 in 1,439,668 control chromosomes in the GnomAD database, with no homozygous occurrence. 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 Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: BRCA2 NM_000059.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2 B:1
• Conservation: PhyloP100: 0.0580

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 Likely_benign. Variant got -1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.13386744).
• BP6: Variant 13-32338692-T-C is Benign according to our data. Variant chr13-32338692-T-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 531384.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=1, Uncertain_significance=2}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BRCA2	NM_000059.4	c.4337T>C	p.Ile1446Thr	missense_variant	11/27	ENST00000380152.8	NP_000050.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
BRCA2	ENST00000380152.8	c.4337T>C	p.Ile1446Thr	missense_variant	11/27	5	NM_000059.4	ENSP00000369497.3
BRCA2	ENST00000530893.7	c.3968T>C	p.Ile1323Thr	missense_variant	11/27	1		ENSP00000499438.2
BRCA2	ENST00000614259.2	n.4337T>C		non_coding_transcript_exon_variant	10/26	2		ENSP00000506251.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.95e-7 AC: 1 AN: 1439668 Hom.: 0 Cov.: 35 AF XY: 0.00 AC XY: 0 AN XY: 712430

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: 9.10e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:2 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Quest Diagnostics Nichols Institute San Juan Capistrano

Jun 18, 2018

- -

Hereditary breast ovarian cancer syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Oct 31, 2017

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. This variant has been reported in an individual affected with breast cancer (PMID: 22729890). This variant is not present in population databases (ExAC no frequency). This sequence change replaces isoleucine with threonine at codon 1446 of the BRCA2 protein (p.Ile1446Thr). The isoleucine residue is weakly conserved and there is a moderate physicochemical difference between isoleucine and threonine. In an experimental study measuring chromosomal damage upon irradiation of patient lymphocytes, cells with this variant showed comparable results to wild-type control cells (PMID: 22729890). -

Hereditary cancer-predisposing syndrome Benign:1

Likely benign, criteria provided, single submitter

curation

University of Washington Department of Laboratory Medicine, University of Washington

Mar 23, 2023

Missense variant in a coldspot region where missense variants are very unlikely to be pathogenic (PMID:31911673). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.076
BayesDel_addAF	Benign	-0.037	T
BayesDel_noAF	Benign	-0.29
CADD	Benign	15
DANN	Benign	0.92
Eigen	Benign	-0.99
Eigen_PC	Benign	-0.95
FATHMM_MKL	Benign	0.025	N
M_CAP	Benign	0.070	D
MetaRNN	Benign	0.13	T;T
MetaSVM	Benign	-0.97	T
PrimateAI	Benign	0.32	T
PROVEAN	Benign	-2.1	N;N
REVEL	Uncertain	0.31
Sift	Benign	0.047	D;D
Sift4G	Benign	0.18	T;T
Vest4		0.40
MutPred		0.47		Gain of disorder (P = 0.0214);Gain of disorder (P = 0.0214);
MVP		0.85
MPC		0.024
ClinPred		0.038	T
GERP RS		-2.5
gMVP		0.19

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: rs1555283730; hg19: chr13-32912829;