Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PM1PM2PM5PP3_ModeratePP5_Moderate
The NM_007294.4(BRCA1):c.5090G>T(p.Cys1697Phe) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. C1697R) has been classified as Pathogenic.
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 10 ACMG points.
PM1
?
PM1 - Located in a mutational hot spot and/or critical and well-established functional domain (e.g., active site of an enzyme) without benign variation
In a hotspot region, there are 12 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 6 benign, 16 uncertain in NM_007294.4
PM2
?
PM2 - Absent from controls (or at extremely low frequency if recessive) in Exome Sequencing Project, 1000 Genomes Project, or Exome Aggregation Consortium
Very rare variant in population databases, with high coverage;
PM5
?
PM5 - Novel missense change at an amino acid residue where a different missense change determined to be pathogenic has been seen before
Other missense variant is known to change same aminoacid residue: Variant chr17-43063937-A-G is described in ClinVar as [Pathogenic]. Clinvar id is 55392.Status of the report is reviewed_by_expert_panel, 3 stars.
PP3
?
PP3 - Multiple lines of computational evidence support a deleterious effect on the gene or gene product (conservation, evolutionary, splicing impact, etc.)
MetaRNN computational evidence supports a deleterious effect, 0.905
PP5
?
PP5 - Reputable source recently reports variant as pathogenic, but the evidence is not available to the laboratory to perform an independent evaluation
Variant 17-43063936-C-A is Pathogenic according to our data. Variant chr17-43063936-C-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 867631.Status of the report is criteria_provided_single_submitter, 1 stars.
Hereditary breast ovarian cancer syndrome Pathogenic:1
Likely pathogenic, criteria provided, single submitter
clinical testing
Invitae
Oct 12, 2021
In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. This variant disrupts the p.Cys1697 amino acid residue in BRCA1. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 11157798, 11389159, 24729269, 28781887, 30209399). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. Experimental studies have shown that this missense change affects BRCA1 function (PMID: 28781887, 30209399). Advanced modeling of experimental studies (such as gene expression, population dynamics, functional pathways, and cell-cycle effects in cell culture) performed at Invitae indicates that this missense variant is expected to disrupt BRCA1 protein function. ClinVar contains an entry for this variant (Variation ID: 867631). This variant has not been reported in the literature in individuals affected with BRCA1-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces cysteine with phenylalanine at codon 1697 of the BRCA1 protein (p.Cys1697Phe). The cysteine residue is highly conserved and there is a large physicochemical difference between cysteine and phenylalanine. -
Breast-ovarian cancer, familial, susceptibility to, 1 Other:1