rs80359253

Positions:

• chr13-32332470-A-T

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_000059.4(BRCA2):​c.992A>T​(p.Lys331Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000139 in 1,442,300 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/19 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. K331E) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: BRCA2 NM_000059.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:4 B:2
• Conservation: PhyloP100: 2.25

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 Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.2262623).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
BRCA2	NM_000059.4	c.992A>T	p.Lys331Ile	missense_variant	10/27	ENST00000380152.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
BRCA2	ENST00000380152.8	c.992A>T	p.Lys331Ile	missense_variant	10/27	5	NM_000059.4	A2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000431 AC: 1 AN: 231826 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 125364

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: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.000181

GnomAD4 exome AF: 0.00000139 AC: 2 AN: 1442300 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 716756

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: 9.04e-7

Gnomad4 OTH exome AF: 0.0000168

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:4 Benign:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:2 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). -
Uncertain significance, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Jul 25, 2022	This missense variant replaces lysine with isoleucine at codon 331 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 been reported in a multifactorial analysis with segregation, tumor pathology, co-occurrence and family history likelihood ratios for pathogenicity of 0.5589, 1.07, 1.0666 and 0.8016, respectively (PMID: 31131967). This variant has been identified in 1/231826 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. -
Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Jan 13, 2023	The p.K331I variant (also known as c.992A>T), located in coding exon 9 of the BRCA2 gene, results from an A to T substitution at nucleotide position 992. The lysine at codon 331 is replaced by isoleucine, an amino acid with dissimilar properties. This alteration was identified in an individual diagnosed with breast cancer (Thomassen M et al. Breast Cancer Res Treat, 2012 Apr;132:1009-23). This amino acid position is not well 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. -

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

Likely benign, no assertion criteria provided	clinical testing	Department of Medical and Surgical Sciences, University of Bologna	Sep 01, 2023	PM2(Supporting)+BP1(Strong) according to ACMG/AMP classification guidelines specified for BRCA1 & BRCA2 (Classification Criteria V1.0.0 2023-09-08 - https://cspec.genome.network/cspec/ui/svi/affiliation/50087) (PMID: 38160042) -
Uncertain significance, no assertion criteria provided	clinical testing	Breast Cancer Information Core (BIC) (BRCA2)	Feb 20, 2004	- -

Hereditary breast ovarian cancer syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Feb 19, 2020

This variant has been reported in individuals in the Breast Cancer Information Core database and has been reported in an individual affected with breast cancer (PMID: 10923033, 21769658). ClinVar contains an entry for this variant (Variation ID: 52920). In summary, this is a rare missense change with uncertain impact on protein function. It has been classified as a Variant of Uncertain Significance. Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). This variant is not present in population databases (ExAC no frequency) . This sequence change replaces lysine with isoleucine at codon 331 of the BRCA2 protein (p.Lys331Ile). The lysine residue is moderately conserved and there is a moderate physicochemical difference between lysine and isoleucine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.15
BayesDel_addAF	Benign	-0.036	T
BayesDel_noAF	Benign	-0.29
CADD	Benign	18
DANN	Benign	0.97
Eigen	Benign	-0.32
Eigen_PC	Benign	-0.36
FATHMM_MKL	Uncertain	0.76	D
M_CAP	Uncertain	0.11	D
MetaRNN	Benign	0.23	T;T
MetaSVM	Benign	-0.86	T
MutationTaster	Benign	1.0	N;N
PrimateAI	Benign	0.35	T
PROVEAN	Benign	-1.9	N;N
REVEL	Benign	0.13
Sift	Uncertain	0.0010	D;D
Sift4G	Uncertain	0.011	D;D
Vest4		0.33
MutPred		0.28		Loss of methylation at K331 (P = 0.0241);Loss of methylation at K331 (P = 0.0241);
MVP		0.87
MPC		0.15
ClinPred		0.78	D
GERP RS		3.1
gMVP		0.14

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: rs80359253; hg19: chr13-32906607;