17-43057147-C-T

Variant names:

• chr17-43057147-C-T
• rs80358079
• NM_007294.4:c.5194-12G>A

Variant summary

Our verdict is Pathogenic. The variant received 6 ACMG points: 6P and 0B. PP4_Strong PP3 PM2_Supporting

This summary comes from the ClinGen Evidence Repository: The c.5194-12G>A variant is an intronic variant occurring in intron 19 of the BRCA1 gene. This variant is absent from gnomAD v2.1 (exomes only, non-cancer subset, read depth ≥25) and gnomAD v3.1 (non-cancer subset, read depth ≥25) (PM2_Supporting met). This BRCA1 intronic variant is located outside of the native donor and acceptor 1,2 splice sites, and the SpliceAI predictor score is 0.96, predicting an impact on splicing (score threshold >0.20) (PP3 met). This variant was reported to result in aberrant mRNA splicing by partial retention of intron 19 (PMIDs: 21673748, 21394826). Another study reported the same aberration as well as exon 20 skipping, however it also reported a higher proportion of full length transcript (PMID:31843900) (PVS1 (RNA) not applied due to conflicting evidence). Multifactorial likelihood ratio analysis using clinically calibrated data produced a combined LR for this variant of 1126348153 (based on Cosegregation LR=6.5; Pathology LR=12.7; Co-occurrence LR=1.3; Family History LR=10799731), above the threshold for Very strong evidence towards pathogenicity (LR >350) (PP4_Very strong met; PMID:31131967, 31853058).In summary, this variant meets the criteria to be classified as a Pathogenic variant for BRCA1-related cancer predisposition based on the ACMG/AMP criteria applied as specified by the ENIGMA BRCA1/2 VCEP (PM2_Supporting, PP3, PP4_Very strong). LINK:https://erepo.genome.network/evrepo/ui/classification/CA003343/MONDO:0011450/092

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: BRCA1 NM_007294.4 intron
• Scores: Splicing: ADA: 0.9997
• Clinical Significance: Pathogenic reviewed by expert panel P:10 U:1 O:1
• Conservation: PhyloP100: 1.48
• Publications: 9 publications found

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: Genomics England PanelApp, Labcorp Genetics (formerly Invitae), Ambry Genetics
• Fanconi anemia, complementation group S

  Inheritance: AR Classification: DEFINITIVE, STRONG, MODERATE, LIMITED Submitted by: G2P, ClinGen, Labcorp Genetics (formerly Invitae), Ambry Genetics
• 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

ACMG classification

Our verdict: Pathogenic. The variant received 6 ACMG points.

• PM2: For more information check the summary or visit ClinGen Evidence Repository.
• PP3: For more information check the summary or visit ClinGen Evidence Repository.
• PP4: For more information check the summary or visit ClinGen Evidence Repository.

Variant Effect in Transcripts

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

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	BRCA1	NM_007294.4	MANE Select	c.5194-12G>A		intron	N/A	NP_009225.1	P38398-1
	BRCA1	NM_001407581.1		c.5260-12G>A		intron	N/A	NP_001394510.1	A0A2R8Y7V5
	BRCA1	NM_001407582.1		c.5260-12G>A		intron	N/A	NP_001394511.1	A0A2R8Y7V5

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	BRCA1	ENST00000357654.9	TSL:1 MANE Select	c.5194-12G>A		intron	N/A	ENSP00000350283.3	P38398-1
	BRCA1	ENST00000471181.7	TSL:1	c.5257-12G>A		intron	N/A	ENSP00000418960.2	P38398-7
	BRCA1	ENST00000470026.6	TSL:1	c.5194-12G>A		intron	N/A	ENSP00000419274.2	P38398-1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1459878 Hom.: 0 Cov.: 30 AF XY: 0.00000275 AC XY: 2 AN XY: 726396

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

African (AFR) AF: 0.00 AC: 0 AN: 33438

American (AMR) AF: 0.00 AC: 0 AN: 44716

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26100

East Asian (EAS) AF: 0.00 AC: 0 AN: 39688

South Asian (SAS) AF: 0.00 AC: 0 AN: 86194

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53394

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5752

European-Non Finnish (NFE) AF: 0.00000180 AC: 2 AN: 1110268

Other (OTH) AF: 0.00 AC: 0 AN: 60328

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.00000037155), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 31

Alfa AF: 0.0000129 Hom.: 0

ClinVar

ClinVar submissions

Significance: Pathogenic

Revision: reviewed by expert panel

Pathogenic	VUS	Benign	Condition
2	1	-	Breast-ovarian cancer, familial, susceptibility to, 1 (3)
2	-	-	Hereditary breast ovarian cancer syndrome (3)
2	-	-	Hereditary cancer-predisposing syndrome (2)
1	-	-	BRCA1-related cancer predisposition (1)
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)
1	-	-	Familial cancer of breast;C2676676:Breast-ovarian cancer, familial, susceptibility to, 1;C4554406:Fanconi anemia, complementation group S (1)
1	-	-	Hereditary breast ovarian cancer syndrome;C2676676:Breast-ovarian cancer, familial, susceptibility to, 1 (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.69
CADD	Pathogenic	29
DANN	Benign	0.64
PhyloP100		1.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Mutation Taster		=3/97	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.90
Splicevardb		3.0
SpliceAI score (max)		0.96		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.96		Position offset: -2
DS_AL_spliceai		0.76		Position offset: -12

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

Other links and lift over

dbSNP: rs80358079; hg19: chr17-41209164;