rs80358027

Positions:

• chr17-43082403-C-A
• chr17-43082403-C-G
• chr17-43082403-C-T

Variant summary

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

The ENST00000357654.9(BRCA1):​c.4357+1G>T variant causes a splice donor 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 Pathogenic (★★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: BRCA1 ENST00000357654.9 splice_donor
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic reviewed by expert panel P:10
• Conservation: PhyloP100: 3.70

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, No cryptic splice site detected. Exon removal results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 17-43082403-C-A is Pathogenic according to our data. Variant chr17-43082403-C-A is described in ClinVar as [Pathogenic]. Clinvar id is 55178.Status of the report is reviewed_by_expert_panel, 3 stars. Variant chr17-43082403-C-A is described in Lovd as [Pathogenic]. Variant chr17-43082403-C-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BRCA1	NM_007294.4	c.4357+1G>T		splice_donor_variant		ENST00000357654.9	NP_009225.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
BRCA1	ENST00000357654.9	c.4357+1G>T		splice_donor_variant		1	NM_007294.4	ENSP00000350283	P4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:10

Revision: reviewed by expert panel

Submissions by phenotype

Breast-ovarian cancer, familial, susceptibility to, 1 Pathogenic:4

Pathogenic, criteria provided, single submitter	clinical testing	Fulgent Genetics, Fulgent Genetics	Aug 27, 2015	- -
Pathogenic, criteria provided, single submitter	clinical testing	Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA), c/o University of Cambridge	Oct 02, 2015	- -
Pathogenic, no assertion criteria provided	clinical testing	Breast Cancer Information Core (BIC) (BRCA1)	Jun 22, 1999	- -
Pathogenic, reviewed by expert panel	curation	Evidence-based Network for the Interpretation of Germline Mutant Alleles (ENIGMA)	Jun 18, 2019	IARC class based on posterior probability from multifactorial likelihood analysis, thresholds for class as per Plon et al. 2008 (PMID: 18951446). Class 5 based on posterior probability = 0.993968 -

not provided Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Jun 20, 2022	Canonical splice site variant predicted to result in a null allele in a gene for which loss of function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (gnomAD); Published functional studies demonstrate a damaging effect: exon 13 skipping (Menendez 2012); Also known as c.4476+1G>T; IVS13+1G>T; This variant is associated with the following publications: (PMID: 19016756, 29161300, 20104584, 25525159, 31131967, 33151324, 31825140, 30702160, 21735045) -
Pathogenic, criteria provided, single submitter	clinical testing	Quest Diagnostics Nichols Institute San Juan Capistrano	Sep 22, 2022	This variant disrupts a canonical splice-donor site and interferes with normal BRCA1 mRNA splicing. This variant has not been reported in large, multi-ethnic general populations (http://gnomad.broadinstitute.org). In the published literature, the variant has been reported in affected individuals or families with breast and/or ovarian cancer (PMIDs: 15533909 (2004), 19016756 (2008), 20104584 (2010), 24797986 (2014), 25452441 (2015), 26681312 (2015), 31825140 (2019), 34413315 (2021)). A functional study found that this variant demonstrated complete skipping of exon 13 (PMID: 21735045 (2012)). Based on the available information, this variant is classified as pathogenic. -

Hereditary cancer-predisposing syndrome Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Ambry Genetics	Oct 17, 2022	The c.4357+1G>T intronic pathogenic mutation results from a G to T substitution one nucleotide after coding exon 11 of the BRCA1 gene. This mutation has been reported in multiple individuals suspected of hereditary breast and/or ovarian cancer (Sugano K et al. Cancer Sci. 2008 Oct; 99(10):1967-76; Borg A et al. Hum. Mutat. 2010 Mar; 31(3):E1200-40; Alemar B et al. PLoS ONE 2017 Nov;12(11):e0187630). In addition, RT-PCR analysis demonstrated that this alteration results in skipping of exon 13 (coding exon 12), which would result in a frameshift and premature protein truncation (Menéndez M et al. Breast Cancer Res. Treat. 2012 Apr;132(3):979-92). Of note, this mutation is also designated as IVS13+1G>T in published literature. In addition to the clinical data presented in the literature, 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 a disease-causing mutation. -
Pathogenic, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Aug 17, 2023	This variant causes a G to T nucleotide substitution at the +1 position of intron 12 of the BRCA1 gene. This variant is also known as IVS13+1G>T based on Breast Cancer Information Core (BIC) nomenclature. RNA studies have shown that this variant causes skipping of exon 12, and is predicted to result in premature truncation of the BRCA1 protein (PMID: 21735045). This variant has been reported in individuals affected with breast cancer and in hereditary breast and ovarian cancer families (PMID: 19016756, 20104584, 21735045, 28294317, 29161300). Different variants affecting the same splice donor site, c.4357+1G>A, c.4357+1G>C, c.4357+2T>A, c.4357+2T>G, and c.4357+2T>C are known to be disease-causing (ClinVar variation ID: 37584, 55177, 1076429, 91629, 55180). 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 Pathogenic. -

Hereditary breast ovarian cancer syndrome Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Nov 13, 2023	This sequence change affects a donor splice site in intron 12 of the BRCA1 gene. RNA analysis indicates that disruption of this splice site induces altered splicing and may result in an absent or disrupted protein product. This variant is not present in population databases (gnomAD no frequency). Disruption of this splice site has been observed in individual(s) with breast cancer (PMID: 15533909, 20104584, 24013928, 24797986, 25085752, 25452441, 26681312). This variant is also known as IVS13+1G>A. ClinVar contains an entry for this variant (Variation ID: 55178). Studies have shown that disruption of this splice site alters mRNA splicing and is expected to lead to the loss of protein expression (PMID: 21735045, 24667779; Invitae). For these reasons, this variant has been classified as Pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Mendelics	Jul 02, 2018	- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.42	D
BayesDel_noAF	Pathogenic	0.36
CADD	Pathogenic	32
DANN	Uncertain	0.99
Eigen	Pathogenic	0.99
Eigen_PC	Pathogenic	0.82
FATHMM_MKL	Uncertain	0.83	D
MutationTaster	Benign	1.0	D;D;D;D;D;D;D;D;D;D;D;D;D;D
GERP RS		5.3

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.94
SpliceAI score (max)		1.0		Details are displayed if max score is > 0.2
DS_DL_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: rs80358027; hg19: chr17-41234420;