rs863224464

Positions:

• chr13-32316461-A-G
• chr13-32316461-A-T

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PVS1 PS1_Moderate PM2 PP5_Moderate

The NM_000059.4(BRCA2):​c.1A>G​(p.Met1?) variant causes a start lost change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: BRCA2 NM_000059.4 start_lost
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 5.08

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 Pathogenic. Variant got 14 ACMG points.

• PVS1: Start lost variant, no new inframe start found.
• PS1: Another start lost variant in NM_000059.4 (BRCA2) was described as [Pathogenic] in Lovd
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 13-32316461-A-G is Pathogenic according to our data. Variant chr13-32316461-A-G is described in ClinVar as [Pathogenic]. Clinvar id is 216026.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BRCA2	NM_000059.4	c.1A>G	p.Met1?	start_lost	2/27	ENST00000380152.8	NP_000050.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
BRCA2	ENST00000380152.8	c.1A>G	p.Met1?	start_lost	2/27	5	NM_000059.4	ENSP00000369497.3
BRCA2	ENST00000530893	c.-365A>G		5_prime_UTR_variant	2/27	1		ENSP00000499438.2
BRCA2	ENST00000614259.2	n.1A>G		non_coding_transcript_exon_variant	1/26	2		ENSP00000506251.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hereditary breast ovarian cancer syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Apr 28, 2019

This sequence change affects the initiator methionine of the BRCA2 mRNA. The next in-frame methionine is located at codon 124. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals with BRCA2-related conditions. ClinVar contains an entry for this variant (Variation ID: 216026). Different variants (c.2T>A, c.2T>C, c.3G>A) affecting the same codon observed here (initiator codon) have been determined to be pathogenic (PMID: 25330149, 14647210, 21769658, 18182601, 24156927, Invitae). This suggests that this variant is also likely to be causative of disease. For these reasons, this variant has been classified as Pathogenic. While this variant is expected to result in an absent protein product, possible rescue of translational initiation by the downstream methionine would lead to the disruption of the N-terminal part of the BRCA2 protein that interacts with PALB2 (residues 18-40), which is critical for BRCA2-mediated homologous recombinational DNA repair (PMID: 16793542, 22678057, 19369211). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.22	D
BayesDel_noAF	Uncertain	0.090
CADD	Benign	20
DANN	Uncertain	0.99
Eigen	Uncertain	0.52
Eigen_PC	Uncertain	0.48
FATHMM_MKL	Uncertain	0.92	D
M_CAP	Pathogenic	0.89	D
MetaRNN	Pathogenic	0.99	D;D
MetaSVM	Benign	-1.0	T
PROVEAN	Benign	-0.96	N;N
REVEL	Uncertain	0.33
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0	D;D
Vest4		0.84
MutPred		0.99		Gain of relative solvent accessibility (P = 0.1571);Gain of relative solvent accessibility (P = 0.1571);
MVP		0.93
ClinPred		1.0	D
GERP RS		5.3
gMVP		0.55

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: rs863224464; hg19: chr13-32890598;