NM_000059.4:c.7806-3C>G

Variant names:

• chr13-32362520-C-G
• rs863224598
• NM_000059.4:c.7806-3C>G

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP3

The NM_000059.4(BRCA2):​c.7806-3C>G variant causes a splice region, intron change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: BRCA2 NM_000059.4 splice_region, intron
• Scores: Splicing: ADA: 0.9968
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:4
• Conservation: PhyloP100: 3.62

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 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
BRCA2	NM_000059.4	c.7806-3C>G		splice_region_variant, intron_variant	Intron 16 of 26	ENST00000380152.8	NP_000050.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
BRCA2	ENST00000380152.8	c.7806-3C>G		splice_region_variant, intron_variant	Intron 16 of 26	5	NM_000059.4	ENSP00000369497.3
BRCA2	ENST00000530893.7	c.7437-3C>G		splice_region_variant, intron_variant	Intron 16 of 26	1		ENSP00000499438.2
BRCA2	ENST00000614259.2	n.7811C>G		non_coding_transcript_exon_variant	Exon 16 of 26	2		ENSP00000506251.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

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

May 10, 2016

Counsyl

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Hereditary cancer-predisposing syndrome Uncertain:1

Jan 12, 2024

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.7806-3C>G intronic variant results from a C to G substitution 3 nucleotides upstream from coding exon 16 in the BRCA2 gene. This nucleotide position is well conserved in available vertebrate species. In silico splice site analysis predicts that this alteration will weaken the native splice acceptor site. RNA studies have demonstrated that this alteration results in a splice defect; the clinical impact of this abnormal splicing is unknown at this time (Ambry internal data). Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Familial cancer of breast Uncertain:1

Mar 12, 2024

Baylor Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Hereditary breast ovarian cancer syndrome Uncertain:1

Aug 11, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). RNA analysis performed to evaluate the impact of this variant on mRNA splicing indicates it does not significantly alter splicing (Invitae). ClinVar contains an entry for this variant (Variation ID: 216259). This variant has not been reported in the literature in individuals affected with BRCA2-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change falls in intron 16 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.46
CADD	Benign	19
DANN	Benign	0.71

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.79
SpliceAI score (max)		0.60		Details are displayed if max score is > 0.2
DS_AL_spliceai		0.60		Position offset: 3

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

Publications

LitVar

Other links and lift over

dbSNP: rs863224598; hg19: chr13-32936657;