NM_007294.4:c.4986+6T>C

Variant names:

• chr17-43070922-A-G
• rs80358086
• NM_007294.4:c.4986+6T>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.4986+6T>C variant causes a splice region, intron change. The variant allele was found at a frequency of 0.00000186 in 1,613,934 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign 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: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: BRCA1 NM_007294.4 splice_region, intron
• Scores: Splicing: ADA: 0.9959
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:24 O:2
• Conservation: PhyloP100: 5.03

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, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 17-43070922-A-G is Pathogenic according to our data. Variant chr17-43070922-A-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 37620.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr17-43070922-A-G is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
BRCA1	NM_007294.4	c.4986+6T>C		splice_region_variant, intron_variant	Intron 15 of 22	ENST00000357654.9	NP_009225.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
BRCA1	ENST00000357654.9	c.4986+6T>C		splice_region_variant, intron_variant	Intron 15 of 22	1	NM_007294.4	ENSP00000350283.3

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152194 Hom.: 0 Cov.: 32

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: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461740 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 727194

Gnomad4 AFR exome AF: 0.0000299

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152194 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74354

Gnomad4 AFR AF: 0.0000241

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.0000151

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:24 Other:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Breast-ovarian cancer, familial, susceptibility to, 1 Pathogenic:9 Other:2

Jan 05, 2022

Laboratorio de Genetica e Diagnostico Molecular, Hospital Israelita Albert Einstein

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

ACMG classification criteria: PS3 supporting, PS4 moderate, PM2 moderate, PP1 supporting, PP3 supporting -

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Brotman Baty Institute, University of Washington

Significance: not provided

Review Status: no classification provided

Collection Method: in vitro

- -

Sep 21, 2015

Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Mar 29, 2024

Baylor Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Feb 09, 2012

Sharing Clinical Reports Project (SCRP)

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

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Breast Cancer Information Core (BIC) (BRCA1)

Significance: not provided

Review Status: no classification provided

Collection Method: clinical testing

- -

Apr 01, 2017

Counsyl

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jul 17, 2023

Victorian Clinical Genetics Services, Murdoch Childrens Research Institute

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as Pathogenic. Following criteria are met: 0102 - Loss of function is a known mechanism of disease in this gene and is associated with Fanconi anaemia, complementation group S (MIM#617883), susceptibility to breast and ovarian cancer (MIM#604370) and susceptibility to pancreatic cancer (MIM#614320). (I) 0108 - This gene is associated with both recessive and dominant disease. Susceptibility to breast and ovarian cancer follows an autosomal dominant inheritance pattern, while Fanconi anaemia is inherited in an autosomal recessive pattern (OMIM). (I) 0112 - The condition associated with this gene has incomplete penetrance. The highest estimate for cancer risk in carriers of pathogenic variants is 80% by the age of 70 years (PMID: 30551077). (I) 0251 - This variant is heterozygous. (I) 0209 - Splice site variant proven to affect splicing of the transcript with uncertain effect on protein sequence. Using semi-nested RT-PCR performed on total RNA isolated from patient peripheral blood cells, this variant was shown to result in a retention of a 69bp sequence in intron 15 which harbours at least one predicted STOP codon (PMID: 10406662). A subsequent study using a saturating genome editing assay demonstrated that this variant resulted in reduced mRNA expression and was functionally classified as a loss of function variant (PMID: 30209399). (SP) 0304 - Variant is present in gnomAD (v3) <0.01 for a condition (1 heterozygote, 0 homozygotes). (SP) 0311 - An alternative nucleotide change at the same non-canonical splice site is present in gnomAD (v2) at a frequency of 0.0000089 (1 heterozygote, 0 homozygotes). 0505 - Abnormal splicing is predicted by in silico tools and affected nucleotide is highly conserved. (SP) 0704 - Another non-canonical splice variant comparable to the one identified in this case has limited previous evidence for pathogenicity. The c.4986+6T>G non-canonical splice variant has been classified as 3 stars by an expert panel; however, it should be noted that the c.4986+6T>A non-canonical splice variant has been classified once as a VUS (ClinVar). (SP) 0801 - This variant has very strong previous evidence of pathogenicity in unrelated individuals. This variant has been classified as likely pathogenic or pathogenic by multiple clinical diagnostic laboratories (ClinVar) and has been reported in multiple individuals across different ethnicities (PMID: 29446198). (SP) 1208 - Inheritance information for this variant is not currently available in this individual. (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -

Oct 02, 2015

Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA), c/o University of Cambridge

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Apr 01, 2019

Division of Medical Genetics, University of Washington

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.5049+6T>C variant (also known as IVS16+6T>C) affects a cryptic splice donor site and leads to an aberrant transcript and truncated protein (Scholl 1999, Houdayer 2012). A different sequence change at the same position has also been shown to result in abnormal splicing (Chen 2006). The c.5049+6T>C variant has been reported in multiple individuals and families with breast and ovarian cancer (Scholl 1999, Zhang 2011, Akbari 2011, Caux-Moncoutier 2011, Biunno 2014). Thus, the c.5049+6T>C variant is interpreted as pathogenic. -

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Diagnostic Laboratory, Department of Genetics, University Medical Center Groningen

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

not provided Pathogenic:5

-

Clinical Genetics Laboratory, Department of Pathology, Netherlands Cancer Institute

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Jul 24, 2015

Eurofins Ntd Llc (ga)

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jun 21, 2024

Quest Diagnostics Nichols Institute San Juan Capistrano

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The BRCA1 c.4986+6T>C variant has been reported in the published literature in individuals and families with breast/ovarian cancer (PMIDs: 21120943 (2011), 21324516 (2011), 21965345 (2011), 24729269 (2014), 28503720 (2017), and 33646313 (2021)). In addition, RNA studies indicated that this variant activates a cryptic splice site and causes an inclusion of extra intronic sequences which encoded a truncated BRCA1 protein (PMIDs: 10406662 (1999), 22505045 (2012), and 23239986 (2012)). This variant has not been reported in large, multi-ethnic general populations (Genome Aggregation Database, http://gnomad.broadinstitute.org). Analysis of this variant using software algorithms for the prediction of the effect of nucleotide changes on splicing yielded predictions that this variant may affect proper BRCA1 mRNA splicing. Based on the available information, this variant is classified as pathogenic. -

May 27, 2022

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Non-canonical splice site variant demonstrated to result in aberrant splicing and a truncated protein (Scholl 1999, Uchikawa 2007); Observed in multiple individuals with personal and/or family histories consistent with Hereditary Breast and Ovarian Cancer (Scholl 1999, Akbari 2011, Lynce 2015, Pal 2015, Rummel 2017); Published functional studies demonstrate a damaging effect: variant classified as non-functional based on a saturation genome editing (SGE) assay measuring cell survival (Findlay 2018); Not observed at a significant frequency in large population cohorts (gnomAD); In silico analysis supports a deleterious effect on splicing; Also known as 5105+6T>C and IVS16+6T>C; This variant is associated with the following publications: (PMID: 26913838, 21965345, 21324516, 23348723, 22505045, 10406662, 24729269, 23239986, 26250392, 26287763, 25782689, 23192404, 28727877, 28087643, 28503720, 30209399, 31159747, 33646313, 30787465, 17851636) -

Jan 01, 2020

GeneKor MSA

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change occurs 6 nucleotides after exon 16 of the BRCA1 gene. This position is conserved in the human genome and is crucial in mRNA processing. This mutation is expected to result in incorrect splicing, alteration in the reading frame and an absent or truncated protein. This variant is also known as IVS16+6T>C and has been reported in the international literature in patients with hereditary breast and ovarian cancer (PMID: 21324516, 21965345, 21120943). Experimental studies have shown that this sequence change creates an aberrant transcript by activating a cryptic splice donor site. Moreover, this prediction has been confirmed experimentally (PMID: 10406662, 22505045). The mutation database Clinvar contains entries for this variant (Variation ID:37620) In summary, this is a rare sequence change that is expected to affect the BRCA1 protein and cause disease. -

Hereditary cancer-predisposing syndrome Pathogenic:3

Oct 01, 2023

Color Diagnostics, LLC DBA Color Health

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant causes a T>C nucleotide substitution at the +6 position of intron 15 of the BRCA1 gene. This variant is also known as IVS16+6T>C in the literature. RNA studies on carrier-derived RNA have found this variant to disrupt splicing in a manner that is expected to result in an absent or non-functional protein product (PMID: 10406662, 22505045). This variant has been reported to be loss-of-function in a haploid cell proliferation assay (PMID: 30209399). This variant has been reported in multiple individuals with personal and/or family history of breast and ovarian cancer (PMID: 10406662, 18703817, 21120943, 21324516, 24729269, 28503720). 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. -

Jun 14, 2022

Ambry Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.4986+6T>C pathogenic mutation results from a T to C substitution 6 nucleotides after coding exon 14 in the BRCA1 gene. This alteration has been identified in multiple patients with early-onset breast cancer (Pal T et al. Cancer. 2015 Dec;121(23):4173-80; Biunno I et al. Fam. Cancer 2014 Sep;13(3):437-44; Rummel SK et al. Breast Cancer Res. Treat. 2017 Aug;164(3):593-601), as well as in ovarian cancer cohorts (Akbari MR et al. J. Med. Genet. 2011 Nov;48(11):783-6; Zhang S et al. Gynecol. Oncol. 2011 May;121(2):353-7). RNA splicing assays have shown that this mutation activates a cryptic splice donor site, resulting in an insertion, frameshift, and premature truncation (Scholl T et al. Am. J. Med. Genet. 1999; 85:113-6; Houdayer C. Hum. Mutat.. 2012 Aug; 33(8):1228-38; Ambry internal data). In addition, one 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). Of note, this alteration is also designated as IVS16+6T>C in published literature. In silico splice site analysis predicts that this alteration will weaken the native splice donor site. Based on the available evidence, this alteration is classified as a pathogenic mutation. -

May 06, 2021

Sema4, Sema4

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: curation

- -

Hereditary breast ovarian cancer syndrome Pathogenic:3

Jan 31, 2014

Research Molecular Genetics Laboratory, Women's College Hospital, University of Toronto

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: research

- -

Jan 15, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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 altered protein product. This variant is not present in population databases (gnomAD no frequency). This variant has been observed in individual(s) with breast and ovarian cancer (PMID: 10406662, 21120943, 21324516, 21965345, 24729269). This variant is also known as IVS16+6T>C. ClinVar contains an entry for this variant (Variation ID: 37620). 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 activation of a cryptic splice donor site, and produces a non-functional protein and/or introduces a premature termination codon (PMID: 10406662, 22505045; internal data). This variant disrupts the c.4986+6T nucleotide in the BRCA1 gene. Other variant(s) that disrupt this nucleotide have been determined to be pathogenic (PMID: 11179017, 16619214, 22160602). This suggests that this nucleotide is clinically significant, and that variants that disrupt this position are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

Nov 05, 2021

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: BRCA1 c.4986+6T>C alters a conserved nucleotide located close to a canonical splice site and therefore could affect mRNA splicing, leading to a significantly altered protein sequence. Several computational tools predict a significant impact on normal splicing: Two predict the variant abolishes the canonical 5' splicing donor site. One predict the variant weakens the canonical 5' splicing donor site. At least one publication reports experimental evidence that this variant affects mRNA splicing by using a cryptic site 65 nucleotides downstream of the canonical 5' splice donor site (Houdayer_2012). The variant was absent in 249776 control chromosomes. c.4986+6T>C has been reported in the literature in multiple individuals affected with Hereditary Breast And Ovarian Cancer Syndrome (example Rebbeck_2018). These data indicate that the variant is very likely to be associated with disease. At least one publication reports experimental evidence evaluating an impact on protein function (example, Findlay_2018). The most pronounced variant effect results in loss of HDR activity. Multiple clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as pathogenic/likely pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -

Breast and/or ovarian cancer Pathogenic:2

May 06, 2015

Foulkes Cancer Genetics LDI, Lady Davis Institute for Medical Research

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Mar 03, 2017

CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Breast-ovarian cancer, familial, susceptibility to, 1;C3280442:Pancreatic cancer, susceptibility to, 4;C4554406:Fanconi anemia, complementation group S Pathogenic:1

Apr 21, 2024

Fulgent Genetics, Fulgent Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Familial cancer of breast;C2676676:Breast-ovarian cancer, familial, susceptibility to, 1;C4554406:Fanconi anemia, complementation group S Pathogenic:1

May 26, 2023

Department of Pathology and Laboratory Medicine, Sinai Health System

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.35
CADD	Benign	20
DANN	Benign	0.93
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.91
SpliceAI score (max)		0.52		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.52		Position offset: 6

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

Publications

LitVar

Other links and lift over

dbSNP: rs80358086; hg19: chr17-41222939;