17-43045792-CTGCCCAAT-C
Variant summary
Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong
The NM_007294.4(BRCA1):c.5470_5477delATTGGGCA(p.Ile1824AspfsTer3) variant causes a frameshift, splice region change. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★★★).
Frequency
Consequence
NM_007294.4 frameshift, splice_region
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Pathogenic. Variant got 18 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes Cov.: 31
GnomAD4 genome Cov.: 31
ClinVar
Submissions by phenotype
Breast-ovarian cancer, familial, susceptibility to, 1 Pathogenic:4
Variant allele predicted to encode a truncated non-functional protein. -
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Breast-ovarian cancer, familial, susceptibility to, 1;C3280442:Pancreatic cancer, susceptibility to, 4;C4554406:Fanconi anemia, complementation group S Pathogenic:2
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PVS1+PM2_Supporting+PS4 -
Breast neoplasm Pathogenic:2
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not provided Pathogenic:2
This frameshift variant causes the premature termination of BRCA1 protein synthesis. In addition, it has been identified in individuals with breast cancer and/or ovarian cancer, as well as in a healthy control in the published literature (PMIDs: 28294317 (2017), 27257965 (2016), 26852015 (2016), 26824983 (2016), 25863477 (2015), 25366075 (2014), 18512148 (2009), 17922413 (2007), 17851763 (2008), 17680524 (2007), 16515586 (2006), 16455195 (2007), and 15117986 (2004)). Based on the available information, this variant is classified as pathogenic. -
This deletion of eight nucleotides in BRCA1 is denoted c.5470_5477delATTGGGCA at the cDNA level and p.Ile1824AspfsX3 (I1824DfsX3) at the protein level. The normal sequence, with the bases that are deleted in braces, is AGCA[ATTGGGCA]GATG. The deletion causes a frameshift, which changes an Isoleucine to an Aspartic Acid at codon 1824, and creates a premature stop codon at position 3 of the new reading frame. Even though this frameshift occurs in the last exon of the gene, and nonsense-mediated decay is not expected to occur, it is significant since the last 40 amino acids are no longer translated, disrupting the BRCT2 domain. This variant is predicted to cause loss of normal protein function through protein truncation. Also reported as BRCA1 5589del8 or 5589_5596delATTGGGCA using alternate nomenclature, this variant has been reported in individuals with a personal and/or family history of early-onset breast and/or ovarian cancer and is a recurrent pathogenic variant in the Chinese population (Choi 2004, Ahn 2007, Hu 2007, Li 2008, Kim 2014, Cao 2016). We consider this variant to be pathogenic. -
Hereditary cancer-predisposing syndrome Pathogenic:2
This variant deletes 8 nucleotides in exon 23 of the BRCA1 gene, creating a premature translation stop signal in the last coding exon. While this variant is not expected to trigger nonsense-mediated decay, the truncation is predicted to delete the C-terminus of the BRCT domain that is important for phosphopeptide binding and DNA damage response (PMID: 25701377). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in numerous individuals affected with hereditary breast and ovarian cancer in the literature and is a highly recurrent mutation in the Chinese population (PMID: 15117986, 16455195, 17680524, 17851763, 22798144, 25366075, 25863477, 26824983, 26848529, 26852015, 27257965, 27393621, 28294317, 29487695, 29752822, 29805665, 30982232, 31054147, 31174498). 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. -
The c.5470_5477delATTGGGCA pathogenic mutation, located in coding exon 22 of the BRCA1 gene, results from a deletion of 8 nucleotides at positions 5470 to 5477, causing a translational frameshift with a predicted alternate stop codon (p.I1824Dfs*3). This mutation (also sometimes designated as 5589del8 in the literature) is recurrent in the Chinese population and has also been identified in Korean breast/ovarian cohorts (Choi D et al. J Clin Oncol. 2004 May 1;22(9):1638-45; Hu Z et al. Zhonghua Yi Xue Yi Chuan Xue Za Zhi. 2007 Aug;24(4):378-81; Chen W et al. Breast Cancer Res. Treat. 2009 Sep; 117(1):55-60; Ahn SH et al. Cancer Lett. 2007 Jan; 245(1-2):90-5; Kim H et al. Breast Cancer Res. Treat. 2012 Aug; 134(3):1315-26; Li WF et al. Breast Cancer Res. Treat. 2008 Jul; 110(1):99-109; Meng H et al. Int J Cancer. 2020 06;146:3044-3052; Wu Y et al. Hereditas. 2020 Dec;157:1; Zeng C et al. Breast Cancer Res Treat. 2020 Jun;181:465-473). This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). In silico splice site analysis predicts that this alteration will result in the creation or strengthening of a novel splice acceptor site. RNA studies have demonstrated that this alteration results in abnormal splicing in the set of samples tested (Ambry internal data). This alteration occurs at the 3' terminus of the BRCA1 gene, is not expected to trigger nonsense-mediated mRNA decay, and only impacts the last 2% of the protein. However, premature stop codons are typically deleterious in nature, and the impacted region is critical for protein function (Ambry internal data). Based on the supporting evidence, this alteration is interpreted as a disease-causing mutation. -
Hereditary breast ovarian cancer syndrome Pathogenic:1
This sequence change creates a premature translational stop signal (p.Ile1824Aspfs*3) in the BRCA1 gene. RNA analysis indicates that this premature translational stop signal induces altered splicing and likely disrupts the C-terminus of the protein. This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individual(s) with breast and/or ovarian cancer (PMID: 15117986, 16455195, 25366075, 25863477, 26824983, 26848529, 26852015, 27257965). This variant is also known as 5589del8. ClinVar contains an entry for this variant (Variation ID: 55591). Studies have shown that this premature translational stop signal results in activation of a cryptic splice site and introduces a new termination codon (internal data). However the mRNA is not expected to undergo nonsense-mediated decay. This variant disrupts a region of the BRCA1 protein in which other variant(s) (p.Arg1835*) have been determined to be pathogenic (PMID: 8554067, 16683254, 24504028). This suggests that this is a clinically significant region of the protein, and that variants that disrupt it are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at