rs431825341

Positions:

• chr13-32329438-TAC-T

Variant summary

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

The NM_000059.4(BRCA2):​c.632-3_632-2del variant causes a splice region, splice polypyrimidine tract, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,248 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 7.0e-7 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: BRCA2 NM_000059.4 splice_region, splice_polypyrimidine_tract, intron
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:7
• Conservation: PhyloP100: 0.677

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 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BRCA2	NM_000059.4	c.632-3_632-2del		splice_region_variant, splice_polypyrimidine_tract_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.632-3_632-2del		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		5	NM_000059.4	ENSP00000369497	A2

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152248 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000147

Gnomad OTH AF: 0.00

GnomAD4 exome Data not reliable, filtered out with message: AS_VQSR AF: 6.95e-7 AC: 1 AN: 1437874 Hom.: 0 AF XY: 0.00000140 AC XY: 1 AN XY: 715956

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: 9.15e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152248 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74384

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000147

Gnomad4 OTH AF: 0.00

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:7

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Apr 12, 2016	This variant is denoted BRCA2 c.632-3_632-2delCA or IVS7-3_IVS7-2delCA and consists of a deletion of two nucleotides at the -2 and -3 position of intron 7 of the BRCA2 gene. Using alternate nomenclature, this variant would be defined as BRCA2 860-3_860-2delCA. The normal sequence with the bases that are deleted in brackets is ctta[ca]gTCA, where the capital letters are exonic and lowercase are intronic. Multiple in silico models predict this variant to destroy the nearby natural acceptor site and to possibly cause abnormal gene splicing; however, in the absence of RNA or functional studies, the actual effect of this variant is unknown. This variant has not, to our knowledge, been published in the literature as pathogenic or benign. BRCA2 c.632-3_632-2delCA 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. The nucleotides that are deleted are conserved across species. Based on currently available information, it is unclear whether BRCA2 c.632-3_632-2delCA is pathogenic or benign. We consider it to be a variant of uncertain significance. -
Uncertain significance, criteria provided, single submitter	clinical testing	Quest Diagnostics Nichols Institute San Juan Capistrano	Sep 21, 2018	- -

Hereditary cancer-predisposing syndrome Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Aug 01, 2023	The c.632-3_632-2delCA intronic variant, located upstream of coding exon 7 in the BRCA2 gene, results from a deletion of two nucleotides at the c.632-3 and c.632-2 positions. In silico splice site analysis for this alteration is inconclusive. RNA studies have demonstrated that this alteration results in an incomplete splice defect; the clinical impact of this abnormal splicing is unknown at this time (Ambry internal data). These nucleotide positions are well conserved in available vertebrate species. In silico splice site analysis for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -
Uncertain significance, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	May 24, 2023	This variant deletes two nucleotides at the -3 and -2 position in intron 7 of the BRCA2 gene. An RNA study using a minigene assay has shown this variant does not impact splicing (PMID: 36446827). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in individuals affected with breast cancer (PMID: 35220195). This variant has not been identified 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. -

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

Uncertain significance, no assertion criteria provided

clinical testing

Sharing Clinical Reports Project (SCRP)

Nov 21, 2007

- -

Familial cancer of breast Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Baylor Genetics

Jun 14, 2023

- -

Hereditary breast ovarian cancer syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Oct 13, 2023

This sequence change falls in intron 7 of the BRCA2 gene. It does not directly change the encoded amino acid sequence of the BRCA2 protein. It affects a nucleotide within the consensus splice site. This variant is not present in population databases (gnomAD no frequency). This variant has been observed in individual(s) with breast cancer (PMID: 25381700). ClinVar contains an entry for this variant (Variation ID: 96837). Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Studies have shown that this variant is associated with altered splicing resulting in unknown protein product impact (Invitae). 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

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.21		Details are displayed if max score is > 0.2
DS_AL_spliceai		0.21		Position offset: 5

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

Publications

LitVar

Other links and lift over

dbSNP: rs431825341; hg19: chr13-32903575;