13-32370396-G-T

Position:

• chr13-32370396-G-T

Variant summary

Our verdict is Likely benign. Variant got -5 ACMG points: 0P and 5B. BP4_Strong BP6

The NM_000059.4(BRCA2):​c.8332-6G>T 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 0.00000411 in 1,459,092 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000041 (0 hom.)
• Consequence: BRCA2 NM_000059.4 splice_region, splice_polypyrimidine_tract, intron
• Scores: Splicing: ADA: 0.0001420
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3 B:5
• Conservation: PhyloP100: -1.30

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 Likely_benign. Variant got -5 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.75).
• BP6: Variant 13-32370396-G-T is Benign according to our data. Variant chr13-32370396-G-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 136570.We mark this variant Likely_benign, oryginal submissions are: {Uncertain_significance=3, Likely_benign=4, Benign=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
BRCA2	NM_000059.4	c.8332-6G>T		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		ENST00000380152.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
BRCA2	ENST00000380152.8	c.8332-6G>T		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		5	NM_000059.4	A2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.0000119 AC: 3 AN: 251374 Hom.: 0 AF XY: 0.0000147 AC XY: 2 AN XY: 135884

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000289

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000544

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000879

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000411 AC: 6 AN: 1459092 Hom.: 0 Cov.: 31 AF XY: 0.00000551 AC XY: 4 AN XY: 726056

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000224

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000252

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000180

Gnomad4 OTH exome AF: 0.0000332

GnomAD4 genome Cov.: 32

Alfa AF: 0.0000434 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3 Benign:5

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not specified Uncertain:1 Benign:1

Uncertain significance, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Jan 03, 2023	Variant summary: BRCA2 c.8332-6G>T alters a conserved nucleotide located close to a canonical splice site and therefore could affect mRNA splicing, leading to a significantly altered protein sequence. 2/4 computational tools predict no significant impact on normal splicing, while 1 predicts a strengthening of the 3' splice acceptor site and 1 predicts a weakening or loss of this site. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 1.2e-05 in 251374 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. To our knowledge, no occurrence of c.8332-6G>T in individuals affected with Hereditary Breast And Ovarian Cancer Syndrome and no experimental evidence demonstrating its impact on protein function have been reported. Four submitters have provided clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation, classifying it as likely benign (n=3) and VUS (n=1). Based on the evidence outlined above, the variant was classified as VUS-possibly benign. -
Benign, criteria provided, single submitter	clinical testing	GeneDx	Feb 17, 2014	This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -

Hereditary cancer-predisposing syndrome Benign:2

Likely benign, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Sep 12, 2016	- -
Likely benign, criteria provided, single submitter	clinical testing	Ambry Genetics	Jul 23, 2014	This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

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

Uncertain significance, criteria provided, single submitter

clinical testing

Counsyl

Feb 20, 2018

- -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Quest Diagnostics Nichols Institute San Juan Capistrano

Jan 17, 2023

To the best of our knowledge, this variant has not been reported in individuals with BRCA2-related conditions in the published literature. The frequency of this variant in the general population, 0.000012 (3/251374 chromosomes (Genome Aggregation Database, http://gnomad.broadinstitute.org)), is uninformative in the assessment of its pathogenicity. Analysis of this variant using software algorithms for the prediction of the effect of nucleotide changes on splicing yielded predictions that this variant does not affect BRCA2 mRNA splicing . Based on the available information, we are unable to determine the clinical significance of this variant. -

BRCA2-related disorder Benign:1

Likely benign, criteria provided, single submitter

clinical testing

PreventionGenetics, part of Exact Sciences

Oct 09, 2020

This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -

Hereditary breast ovarian cancer syndrome Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Invitae

Jan 21, 2024

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.75
CADD	Benign	4.5
DANN	Benign	0.60

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.00014
dbscSNV1_RF	Benign	0.048
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: rs587780872; hg19: chr13-32944533;