chr13-32394934-G-A

Position:

• chr13-32394934-G-A

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000059.4(BRCA2):​c.9501+1G>A variant causes a splice donor, intron change. The variant allele was found at a frequency of 0.00000205 in 1,461,654 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: BRCA2 NM_000059.4 splice_donor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:7
• Conservation: PhyloP100: 6.47

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 18 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, No cryptic splice site detected. Exon removal results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 13-32394934-G-A is Pathogenic according to our data. Variant chr13-32394934-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 52853.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr13-32394934-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BRCA2	NM_000059.4	c.9501+1G>A		splice_donor_variant, intron_variant		ENST00000380152.8	NP_000050.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
BRCA2	ENST00000380152.8	c.9501+1G>A		splice_donor_variant, intron_variant		5	NM_000059.4	ENSP00000369497.3
BRCA2	ENST00000530893.7	c.9132+1G>A		splice_donor_variant, intron_variant		1		ENSP00000499438.2
BRCA2	ENST00000614259.2	n.*1559+1G>A		splice_donor_variant, intron_variant		2		ENSP00000506251.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461654 Hom.: 0 Cov.: 31 AF XY: 0.00000275 AC XY: 2 AN XY: 727116

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: 0.0000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:7

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Apr 01, 2019	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Clinical Genetics Laboratory, Skane University Hospital Lund	May 27, 2022	- -

Hereditary cancer-predisposing syndrome Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Aug 15, 2022	This variant causes a G to A nucleotide substitution at the +1 position of intron 25 of the BRCA2 gene. An RNA study has shown that this variant causes the out-of-frame skipping of exon 25, resulting in premature truncation, in the analysis of RNA from two carriers (PMID: 29310832). To our knowledge, functional studies have not been reported for this variant. This variant has been detected in individuals affected with breast and/or ovarian cancer (PMID: 29310832, 30720863, 32963034; Color internal data). This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). Loss of BRCA2 function is a known mechanism of disease (clinicalgenome.org). Based on the available evidence, this variant is classified as Pathogenic. -
Likely pathogenic, criteria provided, single submitter	clinical testing	Ambry Genetics	Dec 12, 2023	The c.9501+1G>A intronic variant results from a G to A substitution one nucleotide after coding exon 24 of the BRCA2 gene. This mutation has been detected in multiple Greek women with a personal history of breast cancer diagnosed before age 40 (Apessos A et al. Cancer Genet, 2018 01;220:1-12; Fostira F et al. J Med Genet, 2020 01;57:53-61). This mutation was also detected in 1/2769 Chinese breast cancer patients (Deng M et al. Int J Cancer, 2019 09;145:1517-1528). This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). This nucleotide position is highly conserved in available vertebrate species. In silico splice site analysis predicts that this alteration will weaken the native splice donor site and may result in the creation or strengthening of a novel splice donor site. RNA studies have demonstrated that this alteration results in abnormal splicing in the set of samples tested (Ambry internal data). As such, this alteration is classified as likely pathogenic. -

Breast-ovarian cancer, familial, susceptibility to, 2 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA), c/o University of Cambridge

Oct 02, 2015

- -

Familial cancer of breast Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

GeneKor MSA

Jan 01, 2020

This variant is a substitution of the first nucleotide base of intron 25 of the BRCA2 gene. This position is conserved in the human and other genomes and might be involved in mRNA processing. Therefore, this variant is expected to disrupt RNA splicing and likely results in an absent or disrupted protein product. The mutation database ClinVar contains entries for this variant (Variation ID: 52853). -

Hereditary breast ovarian cancer syndrome Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 06, 2024

This sequence change affects a donor splice site in intron 25 of the BRCA2 gene. RNA analysis indicates that disruption of this splice site induces altered splicing and may result in an absent or disrupted protein product. This variant is not present in population databases (gnomAD no frequency). Disruption of this splice site has been observed in individual(s) with breast cancer (PMID: 29310832, 30720863, 31209999, 34645131). ClinVar contains an entry for this variant (Variation ID: 52853). Studies have shown that disruption of this splice site results in skipping of exon 25 and introduces a premature termination codon (PMID: 29310832). The resulting mRNA is expected to undergo nonsense-mediated decay. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.40	D
BayesDel_noAF	Pathogenic	0.34
CADD	Pathogenic	33
DANN	Uncertain	0.99
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	1.0
FATHMM_MKL	Uncertain	0.97	D
GERP RS		5.9

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		0.99		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.34		Position offset: 33
DS_DL_spliceai		0.99		Position offset: -1

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs397508058; hg19: chr13-32969071;