Genetic Variant NM_007294.4:c.5251C>T (chr17-43057078-G-A) – ACMG Classification: Pathogenic (12 pts)

Variant summary

Our verdict is The variant received 12 classification points (ACGS-UK Somatic Oncogenicity v2025): 12P and 0B. O1_ModerateO2_Very_StrongO3_SupportingO4_Supporting

The NM_007294.4(BRCA1):c.5251C>T (p.Arg1751*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant is predicted to lead to nonsense-mediated mRNA decay (NMD). The gene BRCA1 is a tumor suppressor gene (CancerMine: 412 TSG, 22 oncogene, 49 driver citations). The gene BRCA1 is a cancer driver gene (CancerMine: 412 TSG, 22 oncogene, 49 driver citations). The variant allele was found at a cumulative frequency of 0.00000274 (AC=4) in the gnomAD database across 1,461,802 control chromosomes (no homozygotes observed). The grpmax filtering allele frequency (95% CI) is 0.0000241. Note: a gnomAD entry for this variant shows a statistical allele-bias signature, consistent with mosaic/somatic contamination (e.g. age-related clonal hematopoiesis) rather than true inherited population frequency — this frequency should not be read as evidence of a common, benign germline variant. In-silico predictor (BayesDel (addAF)) classifies this variant as likely damaging/oncogenic. Splicing prediction tools (SpliceAI) predict no significant impact on normal splicing. Variant has been reported in ClinVar as Pathogenic/Likely Pathogenic (★★★). ClinVar reports functional evidence for this variant: "SCV000108685: Published functional studies demonstrate a damaging effect: unable to support viability in a haploid cell line (Findlay 2018)" and additional evidence is available in ClinVar. The variant has been observed in cBioPortal in 12 samples across 10 studies and 7 cancer types; somatic enrichment level: SUPPORTING (Observed repeatedly in cBioPortal somatic datasets.). This exact variant is curated in the UniProt human variants database as Uncertain Significance, associated with Adenomas and Adenocarcinomas; it is also listed as a COSMIC curated somatic variant.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 31)

Exomes 𝑓: 0.0000027 ( 0 hom. )

Consequence

BRCA1
NM_007294.4 stop_gained

Scores

Clinical Significance

Pathogenic reviewed by expert panel P:47O:1

Conservation

PhyloP100: 2.15

Publications

125 publications found

Variant links:

Genes affected

BRCA1 (HGNC:1100): (BRCA1 DNA repair associated) This gene encodes a 190 kD nuclear phosphoprotein that plays a role in maintaining genomic stability, and it also acts as a tumor suppressor. The BRCA1 gene contains 22 exons spanning about 110 kb of DNA. The encoded protein combines with other tumor suppressors, DNA damage sensors, and signal transducers to form a large multi-subunit protein complex known as the BRCA1-associated genome surveillance complex (BASC). This gene product associates with RNA polymerase II, and through the C-terminal domain, also interacts with histone deacetylase complexes. This protein thus plays a role in transcription, DNA repair of double-stranded breaks, and recombination. Mutations in this gene are responsible for approximately 40% of inherited breast cancers and more than 80% of inherited breast and ovarian cancers. Alternative splicing plays a role in modulating the subcellular localization and physiological function of this gene. Many alternatively spliced transcript variants, some of which are disease-associated mutations, have been described for this gene, but the full-length natures of only some of these variants has been described. A related pseudogene, which is also located on chromosome 17, has been identified. [provided by RefSeq, May 2020]

BRCA1 Gene-Disease associations (from GenCC):

BRCA1-related cancer predisposition
Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
breast-ovarian cancer, familial, susceptibility to, 1
Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, Genomics England PanelApp
Fanconi anemia, complementation group S
Inheritance: AR Classification: DEFINITIVE, STRONG, MODERATE, LIMITED Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, G2P, ClinGen
pancreatic cancer, susceptibility to, 4
Inheritance: AD Classification: MODERATE Submitted by: Genomics England PanelApp
hereditary breast ovarian cancer syndrome
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
Fanconi anemia
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

BRCA1 links:

Genome browser will be placed here

new If you want to explore the variant's impact on the transcript NM_007294.4, check out the Mutation Effect Viewer. This is especially useful for frameshift variants or if you want to visualize the effect of exon loss / intron retention.

Classification according to ACGS-UK Somatic Oncogenicity v2025

Specifications for BRCA1 are available in the ClinGen Criteria Specification Registry and recommended for reference when assigning criteria.

Classification was made for transcript

Our verdict: Pathogenic. The variant received 12 points.

TSG gene: ClinVar germline P/LP ★★+ — Moderate (O1); O1 contributing sources (2.0 pts): ClinVar germline P/LP in TSG (★★★)

Frameshift/stop-gained, NMD predicted, LoF oncogenic mechanism — O2 very strong (+8); Use caution in the presence of multiple transcripts; Gene confirmed as TSG in CancerMine (TSG: 412 citations, oncogene: 22 citations, driver: 49 citations).; Frameshift/stop-gained. NMD predicted: true. LoF mechanism: true. Downstream pathogenic count: 0.

Very rare in gnomAD (popmax AF <0.01%) — O3 supporting; GnomAD effective popmax AF = 0.000024 — very rare (O3 supporting [+1])

Variant Effect in Transcripts

Automated classification analysis was done for transcript: NM_007294.4. You can select a different transcript below to see updated classification assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
BRCA1	NM_007294.4	MANE Select	c.5251C>T	p.Arg1751*	stop_gained	Exon 19 of 23	NP_009225.1	P38398-1
BRCA1	NM_001407581.1		c.5317C>T	p.Arg1773*	stop_gained	Exon 20 of 24	NP_001394510.1	A0A2R8Y7V5
BRCA1	NM_001407582.1		c.5317C>T	p.Arg1773*	stop_gained	Exon 20 of 24	NP_001394511.1	A0A2R8Y7V5

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
BRCA1	ENST00000357654.9	TSL:1 MANE Select	c.5251C>T	p.Arg1751*	stop_gained	Exon 19 of 23	ENSP00000350283.3	P38398-1
BRCA1	ENST00000471181.7	TSL:1	c.5314C>T	p.Arg1772*	stop_gained	Exon 20 of 24	ENSP00000418960.2	P38398-7
BRCA1	ENST00000470026.6	TSL:1	c.5251C>T	p.Arg1751*	stop_gained	Exon 19 of 23	ENSP00000419274.2	P38398-1

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152116

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

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

GnomAD2 exomes

AF:

0.0000119

AC:

AN:

251492

AF XY:

0.0000147

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000544

Gnomad FIN exome

AF:

0.0000462

Gnomad NFE exome

AF:

0.00000879

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000274

AC:

AN:

1461802

Hom.:

Cov.:

AF XY:

0.00000413

AC XY:

AN XY:

727206

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33476

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26128

East Asian (EAS)

AF:

0.0000252

AC:

AN:

39698

South Asian (SAS)

AF:

0.00

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.0000187

AC:

AN:

53416

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5762

European-Non Finnish (NFE)

AF:

0.00000180

AC:

AN:

1111948

Other (OTH)

AF:

0.00

AC:

AN:

60392

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.463

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152116

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74302

show subpopulations

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.0000241

AC:

AN:

41428

American (AMR)

AF:

0.00

AC:

AN:

15256

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5190

South Asian (SAS)

AF:

0.00

AC:

AN:

4832

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10606

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68016

Other (OTH)

AF:

0.00

AC:

AN:

2090

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0.00000037155), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.325

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.00000456

Hom.:

Bravo

AF:

0.00000756

ClinVar

ClinVar submissions

Significance:Pathogenic

Revision:reviewed by expert panel

View on ClinVar

Pathogenic

VUS

Benign

Condition

Breast-ovarian cancer, familial, susceptibility to, 1 (22)

not provided (11)

Hereditary breast ovarian cancer syndrome (6)

Hereditary cancer-predisposing syndrome (4)

Breast and/or ovarian cancer (1)

Breast neoplasm (1)

Familial cancer of breast (1)

Familial cancer of breast;C2676676:Breast-ovarian cancer, familial, susceptibility to, 1;C3280442:Pancreatic cancer, susceptibility to, 4;C4554406:Fanconi anemia, complementation group S (1)

Inherited ovarian cancer (without breast cancer) (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.43

BayesDel_noAF

Pathogenic

0.55

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

Eigen

Uncertain

0.54

Eigen_PC

Uncertain

0.36

FATHMM_MKL

Uncertain

0.77

PhyloP100

2.2

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Mutation Taster

=0/200

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

Splicevardb

2.0

SpliceAI score (max)

0.010

Details are displayed if max score is > 0.2

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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

Classification according to ACGS-UK Somatic Oncogenicity v2025

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over