Genetic Information

Gene & Transcript Details

Gene
BRCA2
Transcript
NM_000059.4 MANE Select
Total Exons
Reference Sequence
NC_000013.10
Alternative Transcripts
IDStatusDetails
NM_000059.4 MANE Select 11954 nt | 200–10456
NM_000059.2 Alternative 11386 nt | 228–10484
NM_000059.3 RefSeq Select 11386 nt | 228–10484

Variant Details

HGVS Notation
NM_000059.4:c.7992T>A
Protein Change
I2664=
Location
Exon 18 (Exon 18 of )
18
5'Exon Structure3'
Functional Consequence
Loss of Function
Alternate Identifiers

Clinical & Population Data

Population Frequency

gnomAD
Global Frequency
0.00319 in 100,000
Extremely Rare
ACMG Criteria Applied PM2
This variant is absent or extremely rare in population databases (PM2 criteria applies).

ClinVar

Open
Classification
Uncertain Significance (VUS)
3 publications
Publications List
PMID: 28339459

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.

PMID: 22505045

Variant summary: BRCA2 c.7992T>A alters a conserved nucleotide resulting in a synonymous change. Consensus agreement among computation tools predict no significant impact on normal splicing. Splicing functional assays demonstrated the variant increases skipping of exon 18 (Thery_2011, Houdayer_2012, Fraile-Bethencourt_2017, Wangensteen_2019), however it is complex to interpret the role of variants with partial splicing anomalies in HBOC under the clinical perspective. The variant allele was found at a frequency of 3.2e-05 in 250460 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.7992T>A has been reported in the literature in an individual affected with breast cancer (Thery_2011). These data do not allow any conclusion about variant significance. At least one publication reports experimental evidence evaluating an impact HDR function, finding no deleterious effect (Mesman_2020). The following publications have been ascertained in the context of this evaluation (PMID: 22505045, 21673748, 23893897, 22962691, 26332594, 26913838, 28339459, 28758972, 31191615, 28794409, 31143303, 32398771). ClinVar contains an entry for this variant (Variation ID: 52463). Based on the evidence outlined above, the variant was classified as likely benign.

Clinical Statement

"This variant has been reported in ClinVar as Uncertain significance (4 clinical laboratories) and as Likely benign (10 clinical laboratories) and as Benign (1 clinical laboratories) and as Likely benign by Evidence-based Network for the Interpretation of Germline Mutant Alleles (ENIGMA) expert panel."

COSMIC Somatic Evidence

Open
COSMIC ID
Recurrence
0 occurrences
PM1 Criteria
Not Applied
COSMIC Database Preview
COSMIC Preview
Accessing full COSMIC database details requires institutional login or subscription.

Functional Impact & Domains

Functional Domain

Hotspot Status
Not a hotspot
Domain Summary
This variant is not located in a mutational hotspot or critical domain.
Related Variants in This Domain
No evidence of other pathogenic variants at this position in gene BRCA2.

Functional Studies & Therapeutic Relevance

Functional Summary

The variant has not been functionally characterized.

Database Previews
OncoKB
OncoKB Preview
JAX-CKB
JAX-CKB Preview

Click on previews to view full database entries. External databases may require institutional access.

Computational Analysis

Pathogenicity Predictions

SpliceAI
Predictor Consensus
Mixed/VUS
PP3 Applied
No
REVEL Score
0.0
Threshold: ≥0.75 = PP3 applied

SpliceAI Scores

Window: ±500bp
Effect Type Score Position
- Acceptor Loss (AL) 0.02 -15 bp
- Donor Loss (DL) 0.0 339 bp
+ Acceptor Gain (AG) 0.0 176 bp
+ Donor Gain (DG) 0.0 -6 bp
High impact (≥0.5) Medium impact (0.2-0.49) Low impact (<0.2)

VCEP Guidelines

Applied ACMG/AMP Criteria (VCEP Specific)

Filter Criteria:
PVS1

PVS1 (Not Applied)

According to VCEP guidelines, PVS1 applies only to null variants in a gene where loss of function is a known mechanism of disease. The variant is a synonymous (I2664=) change, not a null variant. Therefore, this criterion is not applied.

PS1

PS1 (Not Applied)

According to VCEP guidelines, PS1 applies when a different nucleotide change results in the same amino acid change as a previously established pathogenic variant. This is a synonymous variant with no amino acid change and no known pathogenic silent variant at this codon. Therefore, this criterion is not applied.

PS2

PS2 (Not Applied)

According to standard ACMG guidelines, PS2 requires confirmed de novo occurrence with parental testing. No de novo data or parental genotyping are available. Therefore, this criterion is not applied.

PS3

PS3 (Not Applied)

According to VCEP guidelines, PS3 requires well-established functional studies demonstrating a damaging effect. No functional assay data exist for this variant. Therefore, this criterion is not applied.

PS4

PS4 (Not Applied)

According to VCEP guidelines, PS4 requires significant enrichment of the variant in affected individuals in well-powered case-control studies. No case-control data are available. Therefore, this criterion is not applied.

PM1

PM1 (Not Applied)

According to VCEP guidelines, PM1 applies to variants located in mutational hot spots or critical functional domains with no benign variation. This is a synonymous change within the DNA-binding domain but does not affect the protein sequence. Therefore, this criterion is not applied.

PM2

PM2 (Not Applied)

According to VCEP guidelines, PM2_Supporting requires absence from gnomAD non-cancer populations. The variant is present at MAF=0.00319% overall and 0.00707% in non-Finnish Europeans. Therefore, this criterion is not applied.

PM3

PM3 (Not Applied)

According to VCEP guidelines, PM3 applies to variants in a patient with Fanconi anemia phenotype with co-occurring BRCA2 variants. No Fanconi anemia phenotype or trans-variant data are available. Therefore, this criterion is not applied.

PM4

PM4 (Not Applied)

According to standard ACMG guidelines, PM4 applies to protein length changes (in-frame indels) not overlapping repetitive regions. This is a synonymous variant with no protein length change. Therefore, this criterion is not applied.

PM5

PM5 (Not Applied)

According to VCEP guidelines, PM5 applies to novel stop-gain variants in an exon where a different pathogenic stop-gain has been observed. This is a synonymous variant. Therefore, this criterion is not applied.

PM6

PM6 (Not Applied)

According to standard ACMG guidelines, PM6 applies to presumed de novo variants without parental confirmation. No de novo evidence is available. Therefore, this criterion is not applied.

PP1

PP1 (Not Applied)

According to VCEP guidelines, PP1 requires segregation data in multiple affected family members. No segregation data are available. Therefore, this criterion is not applied.

PP2

PP2 (Not Applied)

According to standard ACMG guidelines, PP2 applies to missense variants in genes with low benign missense variation. This is a synonymous variant. Therefore, this criterion is not applied.

PP3

PP3 (Not Applied)

According to VCEP guidelines, PP3 applies to missense or predicted splicing variants (SpliceAI ≥0.2). SpliceAI score is 0.02 (<0.2), and there is no protein change. Therefore, this criterion is not applied.

PP4

PP4 (Not Applied)

According to VCEP guidelines, PP4 requires a highly specific phenotype and multifactorial likelihood data. No such clinical data are available. Therefore, this criterion is not applied.

PP5

PP5 (Not Applied)

According to standard ACMG guidelines, PP5 applies when multiple reputable sources report the variant as pathogenic. ClinVar submissions are conflicting (VUS, likely benign, benign). Therefore, this criterion is not applied.

BA1

BA1 (Not Applied)

According to VCEP guidelines, BA1 requires population frequency (FAF) >0.1%. The variant MAF=0.00319% is well below this threshold. Therefore, this criterion is not applied.

BS1

BS1 (Supporting)

According to VCEP guidelines, BS1_Supporting: "Filter allele frequency (FAF) is above 0.002% and ≤0.01% in gnomAD non-founder populations." The variant MAF=0.00707% in non-Finnish Europeans falls within this range. Therefore, this criterion is applied at Supporting strength.

BS2

BS2 (Not Applied)

According to VCEP guidelines, BS2 applies in healthy adults without Fanconi anemia features. No systematic healthy cohort data are available. Therefore, this criterion is not applied.

BS3

BS3 (Not Applied)

According to VCEP guidelines, BS3 requires well-established functional studies showing no damaging effect. No such data exist. Therefore, this criterion is not applied.

BS4

BS4 (Not Applied)

According to VCEP guidelines, BS4 applies to lack of segregation in affected family members. No segregation data are available. Therefore, this criterion is not applied.

BP1

BP1 (Not Applied)

According to VCEP guidelines, BP1_Strong applies to silent or missense variants outside critical domains with no predicted splicing. Although this is silent, it lies within the DNA-binding domain. Therefore, this criterion is not applied.

BP2

BP2 (Not Applied)

According to VCEP guidelines, BP2 applies when observed in trans with a pathogenic variant for a dominant disorder. No such co-occurrence data are available. Therefore, this criterion is not applied.

BP3

BP3 (Not Applied)

According to standard ACMG guidelines, BP3 applies to in-frame indels in repetitive regions. This is a single-nucleotide synonymous variant. Therefore, this criterion is not applied.

BP4

BP4 (Supporting)

According to VCEP guidelines, BP4_Supporting: "Silent variant inside a potentially clinically important functional domain and no predicted impact via splicing (SpliceAI ≤0.1)." The variant is synonymous in the DNA-binding domain (aa2481-3186) and SpliceAI score=0.02. Therefore, this criterion is applied at Supporting strength.

BP5

BP5 (Not Applied)

According to VCEP guidelines, BP5 applies when co-observed with a pathogenic variant in another gene with no specific phenotype. No such data are available. Therefore, this criterion is not applied.

BP6

BP6 (Not Applied)

According to standard ACMG guidelines, BP6 applies when multiple sources report as benign without evidence. ClinVar submissions are mixed including likely benign and benign but not unanimously. Therefore, this criterion is not applied.

BP7

BP7 (Supporting)

According to VCEP guidelines, BP7_Supporting: "Silent variant inside a potentially clinically important functional domain if BP4 is met." BP4 has been applied. Therefore, this criterion is applied at Supporting strength.