Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong
The NM_007294.4(BRCA1):c.4379del(p.Ser1460IlefsTer6) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★★★). Synonymous variant affecting the same amino acid position (i.e. S1460S) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.
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]
Verdict is Pathogenic. Variant got 18 ACMG points.
PVS1
Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
PM2
Very rare variant in population databases, with high coverage;
PP5
Variant 17-43076592-AC-A is Pathogenic according to our data. Variant chr17-43076592-AC-A is described in ClinVar as [Pathogenic]. Clinvar id is 186693.Status of the report is reviewed_by_expert_panel, 3 stars. Variant chr17-43076592-AC-A is described in Lovd as [Pathogenic]. Variant chr17-43076592-AC-A is described in Lovd as [Pathogenic].
Hereditary breast ovarian cancer syndrome Pathogenic:2
Pathogenic, criteria provided, single submitter
clinical testing
Invitae
Feb 20, 2022
For these reasons, this variant has been classified as Pathogenic. ClinVar contains an entry for this variant (Variation ID: 186693). This variant has not been reported in the literature in individuals affected with BRCA1-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change creates a premature translational stop signal (p.Ser1460Ilefs*6) in the BRCA1 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in BRCA1 are known to be pathogenic (PMID: 20104584). -
Pathogenic, criteria provided, single submitter
clinical testing
Women's Health and Genetics/Laboratory Corporation of America, LabCorp
Dec 07, 2023
Variant summary: BRCA1 c.4379delG (p.Ser1460IlefsX6) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. Variants downstream of this position have been classified as pathogenic by our laboratory. The variant was absent in 251060 control chromosomes (gnomAD). c.4379delG has been reported in the literature in at-least one individual affected with Hereditary Breast And Ovarian Cancer Syndrome (example: Shah_2018). The following publication has been ascertained in the context of this evaluation (PMID: 29785135). Two submitters (including an expert panel ENIGMA) have cited clinical-significance assessments for this variant to ClinVar after 2014. All submitters classified the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -
Breast-ovarian cancer, familial, susceptibility to, 1 Pathogenic:1
Pathogenic, reviewed by expert panel
curation
Evidence-based Network for the Interpretation of Germline Mutant Alleles (ENIGMA)
Sep 08, 2016
Variant allele predicted to encode a truncated non-functional protein. -
The c.4379delG pathogenic mutation (also known as 4498delG), located in coding exon 12 of the BRCA1 gene, results from a deletion of one nucleotide at position 4379, causing a translational frameshift with a predicted alternate stop codon. Since frameshifts are typically deleterious in nature, this alteration is interpreted as a disease-causing mutation (ACMG Recommendations for Standards for Interpretation and Reporting of Sequence Variations. Revision 2007. Genet Med. 2008;10:294). -