17-43071239-C-G

Variant names:

• chr17-43071239-C-G
• rs80358008
• NM_007294.4:c.4676-1G>C

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_007294.4(BRCA1):​c.4676-1G>C variant causes a splice acceptor, intron change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: BRCA1 NM_007294.4 splice_acceptor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:6
• Conservation: PhyloP100: 3.83

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 18 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 11, offset of 2, new splice context is: ttctcccattcctttcacAGgga. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 17-43071239-C-G is Pathogenic according to our data. Variant chr17-43071239-C-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 441389.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr17-43071239-C-G is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
BRCA1	NM_007294.4	c.4676-1G>C		splice_acceptor_variant, intron_variant	Intron 14 of 22	ENST00000357654.9	NP_009225.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
BRCA1	ENST00000357654.9	c.4676-1G>C		splice_acceptor_variant, intron_variant	Intron 14 of 22	1	NM_007294.4	ENSP00000350283.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:6

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:2

-

Clinical Genetics Laboratory, Department of Pathology, Netherlands Cancer Institute

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

-

Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Hereditary cancer-predisposing syndrome Pathogenic:2

Aug 29, 2022

Color Diagnostics, LLC DBA Color Health

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant causes a G to C nucleotide substitution at the -1 position of intron 14 of the BRCA1 gene. Splice site prediction tools suggest that this variant may have a significant impact on RNA splicing. Although this prediction has not been confirmed in published RNA studies, this variant is expected to result in an absent or disrupted protein product. To our knowledge, this variant has not been reported in individuals affected with hereditary cancer in the literature. However, a different mutation at the same position with similar predicted splicing impact, c.4676-1G>A, has been reported in three individuals affected with breast cancer (PMID: 11448907, 25452441) and has been reported by a multifactorial analysis with segregation, co-occurrence and family history likelihood ratios for pathogenicity of 3.7504, 2.0153 and 32.3133, respectively (PMID: 31131967), This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). Loss of BRCA1 function is a known mechanism of disease (clinicalgenome.org). Based on the available evidence, this variant is classified as Likely Pathogenic. -

Oct 24, 2016

Ambry Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.4676-1G>C intronic variant results from a G to C substitution one nucleotide upstream from coding exon 14 of the BRCA1 gene. This variant was not reported in population based cohorts in the following databases: Database of Single Nucleotide Polymorphisms (dbSNP), NHLBI Exome Sequencing Project (ESP), and 1000 Genomes Project. In the ESP, this variant was not observed in 6503 samples (13006 alleles) with coverage at this position. To date, this alteration has been detected with an allele frequency of approximately 0.0003% (greater than 300000 alleles tested) in our clinical cohort. This nucleotide position is highly conserved in available vertebrate species. Using two different splice site prediction tools, this alteration is predicted by BDGP to abolish the native splice acceptor site, and is predicted to weaken (but not abolish) the efficiency of the native splice acceptor site by ESEfinder; however, direct evidence is unavailable. Alterations that disrupt the canonical splice site are expected to cause aberrant splicing, resulting in an abnormal protein or a transcript that is subject to nonsense-mediated mRNA decay. As such, this alteration is classified as likely pathogenic. -

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

Oct 14, 2021

Baylor Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Hereditary breast ovarian cancer syndrome Pathogenic:1

Feb 26, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant has been reported in an individual in the Leiden Open-source Variation Database (PMID: 21520333). This sequence change affects an acceptor splice site in intron 14 of the BRCA1 gene. It is expected to disrupt RNA splicing and likely results in an absent or disrupted protein product. In summary, donor and acceptor splice site variants are typically loss-of-function (PMID: 16199547), and loss-of-function variants in BRCA1 are known to be pathogenic (PMID: 20104584). However, without additional functional and/or genetic data, this variant has been classified as Likely Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.19	D
BayesDel_noAF	Uncertain	0.030
CADD	Pathogenic	34
DANN	Benign	0.97
Eigen	Pathogenic	0.89
Eigen_PC	Pathogenic	0.68
FATHMM_MKL	Uncertain	0.91	D
GERP RS		4.8

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.77
SpliceAI score (max)		1.0		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.99		Position offset: -3
DS_AL_spliceai		1.0		Position offset: -1

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

Publications

LitVar

Other links and lift over

dbSNP: rs80358008; hg19: chr17-41223256; COSMIC: COSV58787736; COSMIC: COSV58787736;