13-32339979-A-G

Position:

• chr13-32339979-A-G

Variant summary

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

The NM_000059.4(BRCA2):​c.5624A>G​(p.Lys1875Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,459,020 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/19 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. K1875T) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: BRCA2 NM_000059.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3 B:1
• Conservation: PhyloP100: 2.07

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 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.17304456).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BRCA2	NM_000059.4	c.5624A>G	p.Lys1875Arg	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.5624A>G	p.Lys1875Arg	missense_variant	11/27	5	NM_000059.4	ENSP00000369497.3
BRCA2	ENST00000530893.7	c.5255A>G	p.Lys1752Arg	missense_variant	11/27	1		ENSP00000499438.2
BRCA2	ENST00000614259.2	n.5624A>G		non_coding_transcript_exon_variant	10/26	2		ENSP00000506251.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1459020 Hom.: 0 Cov.: 47 AF XY: 0.00 AC XY: 0 AN XY: 725570

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: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000378

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:1 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	Ambry Genetics	May 20, 2019	The p.K1875R variant (also known as c.5624A>G), located in coding exon 10 of the BRCA2 gene, results from an A to G substitution at nucleotide position 5624. The lysine at codon 1875 is replaced by arginine, an amino acid with highly similar properties. 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. -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Jan 11, 2016

This variant is denoted BRCA2 c.5624A>G at the cDNA level, p.Lys1875Arg (K1875R) at the protein level, and results in the change of a Lysine to an Arginine (AAG>AGG). Using alternate nomenclature, this variant would be defined as BRCA2 5852A>G. This variant has not, to our knowledge, been published in the literature as pathogenic or benign. BRCA2 Lys1875Arg 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 Lysine and Arginine share similar properties, this is considered a conservative amino acid substitution. BRCA2 Lys1875Arg occurs at a position that is not conserved and is not located in a known functional domain (Borg 2010). In silico analyses predict that this variant is unlikely to alter protein structure or function. Based on currently available evidence, it is unclear whether BRCA2 Lys1875Arg is a pathogenic or benign variant. We consider it to be a variant of uncertain significance. -

Hereditary breast ovarian cancer syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Sep 01, 2021

This sequence change replaces lysine with arginine at codon 1875 of the BRCA2 protein (p.Lys1875Arg). The lysine residue is moderately conserved and there is a small physicochemical difference between lysine and arginine. This variant is not present in population databases (ExAC no frequency). 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: 142607). Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The arginine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. 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	0.085
BayesDel_addAF	Benign	-0.0011	T
BayesDel_noAF	Benign	-0.24
CADD	Benign	8.4
DANN	Benign	0.92
Eigen	Benign	-0.57
Eigen_PC	Benign	-0.65
FATHMM_MKL	Benign	0.38	N
M_CAP	Benign	0.039	D
MetaRNN	Benign	0.17	T;T
MetaSVM	Benign	-0.82	T
PrimateAI	Benign	0.29	T
PROVEAN	Benign	-1.7	N;N
REVEL	Benign	0.29
Sift	Benign	0.14	T;T
Sift4G	Benign	0.35	T;T
Vest4		0.28
MutPred		0.52		Loss of ubiquitination at K1875 (P = 0.011);Loss of ubiquitination at K1875 (P = 0.011);
MVP		0.90
MPC		0.020
ClinPred		0.16	T
GERP RS		2.0
gMVP		0.17

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: rs587782583; hg19: chr13-32914116;