chr17-43067698-G-C

Position:

• chr17-43067698-G-C

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PM2 PP3 PP5_Very_Strong

The NM_007294.4(BRCA1):​c.4987-3C>G variant causes a splice region, splice polypyrimidine tract, intron change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency: Genomes: not found (cov: 30)
• Consequence: BRCA1 NM_007294.4 splice_region, splice_polypyrimidine_tract, intron
• Scores: Splicing: ADA: 0.9995
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:2 O:1
• Conservation: PhyloP100: 4.40

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]

ACMG classification

Verdict is Pathogenic. Variant got 11 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, max_spliceai. No scorers claiming Uncertain. Scorers claiming Benign: dbscSNV1_RF.
• PP5: Variant 17-43067698-G-C is Pathogenic according to our data. Variant chr17-43067698-G-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 55346.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr17-43067698-G-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BRCA1	NM_007294.4	c.4987-3C>G		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		ENST00000357654.9	NP_009225.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
BRCA1	ENST00000357654.9	c.4987-3C>G		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		1	NM_007294.4	ENSP00000350283	P4

Frequencies

GnomAD3 genomes Cov.: 30

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 30

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:2 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hereditary cancer-predisposing syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

May 26, 2021

The c.4987-3C>G intronic pathogenic mutation results from a C to G substitution 3 nucleotides upstream from coding exon 15 in the BRCA1 gene. This nucleotide position is highly conserved in available vertebrate species. Multiple different RNA studies have found that this alteration produces a substantial amount of aberrant, frameshifting transcript (Ambry internal data; Brandão RD et al. Breast Cancer Res Treat, 2012 Jan;131:723-5; Brandão RD et al. Breast Cancer Res Treat, 2011 Oct;129:971-82). One functional study found that this nucleotide substitution is non-functional in a high-throughput, genome editing, haploid cell survival assay. (Findlay GM et al. Nature, 2018 10;562:217-222). Other alterations impacting the same acceptor site (c.4987A>T, c.4987-1G>A, c.4987-5T>A) have been shown to have a similar impact on splicing in (Bonnet C et al. J Med Genet, 2008 Jul;45:438-46; Ahlborn LB et al. Breast Cancer Res Treat, 2015 Apr;150:289-98; Colombo M et al. PLoS One, 2013 Feb;8:e57173). Based on the supporting evidence, this alteration is interpreted as a disease-causing mutation. -

Hereditary breast ovarian cancer syndrome Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Oct 28, 2021

This sequence change falls in intron 15 of the BRCA1 gene. It does not directly change the encoded amino acid sequence of the BRCA1 protein. RNA analysis indicates that this variant induces altered splicing and may result in an absent or disrupted protein product. This variant is not present in population databases (gnomAD no frequency). This variant has been observed in individual(s) with a personal and/or family history of breast and/or ovarian cancer (PMID: 21638052, 29907814). ClinVar contains an entry for this variant (Variation ID: 55346). Algorithms developed to predict the effect of variants on protein structure and function are not available or were not evaluated for this variant. Experimental studies have shown that this variant affects BRCA1 function (PMID: 30209399). Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Studies have shown that this variant results in skipping of exon 16 (also known as exon 17) and introduces a premature termination codon (PMID: 21638052, 22113256). The resulting mRNA is expected to undergo nonsense-mediated decay. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -

Breast-ovarian cancer, familial, susceptibility to, 1 Other:1

not provided, no classification provided

in vitro

Brotman Baty Institute, University of Washington

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Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.38
CADD	Benign	19
DANN	Benign	0.84

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Benign	0.66
SpliceAI score (max)		0.73		Details are displayed if max score is > 0.2
DS_AL_spliceai		0.73		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: rs397509213; hg19: chr17-41219715;