Our verdict is Pathogenic. Variant got 16 ACMG points: 16P and 0B. PM1PM2PM5PP3_ModeratePP5_Very_Strong
The ENST00000357654.9(BRCA1):c.5054C>T(p.Thr1685Ile) variant causes a missense change. The variant allele was found at a frequency of 0.00000186 in 1,612,146 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. T1685A) 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 16 ACMG points.
PM1
In a hotspot region, there are 8 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 7 benign, 17 uncertain in ENST00000357654.9
PM2
Very rare variant in population databases, with high coverage;
PM5
Other missense variant is known to change same aminoacid residue: Variant chr17-43067629-T-C is described in ClinVar as [Pathogenic]. Clinvar id is 55364.Status of the report is reviewed_by_expert_panel, 3 stars.
PP3
MetaRNN computational evidence supports a deleterious effect, 0.867
PP5
Variant 17-43067628-G-A is Pathogenic according to our data. Variant chr17-43067628-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 55365.Status of the report is reviewed_by_expert_panel, 3 stars. Variant chr17-43067628-G-A is described in Lovd as [Pathogenic]. Variant chr17-43067628-G-A is described in Lovd as [Pathogenic].
Breast-ovarian cancer, familial, susceptibility to, 1 Pathogenic:4Uncertain:1Other:1
Uncertain significance, no assertion criteria provided
clinical testing
Breast Cancer Information Core (BIC) (BRCA1)
Feb 20, 2004
- -
not provided, no classification provided
in vitro
Brotman Baty Institute, University of Washington
-
- -
Pathogenic, no assertion criteria provided
case-control
Molecular Oncology, Hospital Universitario Central de Asturias (HUCA)
May 24, 2021
- -
Pathogenic, no assertion criteria provided
clinical testing
BRCAlab, Lund University
Mar 02, 2020
- -
Pathogenic, reviewed by expert panel
curation
Evidence-based Network for the Interpretation of Germline Mutant Alleles (ENIGMA)
Aug 10, 2015
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 = 0.999 -
Pathogenic, criteria provided, single submitter
clinical testing
Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA), c/o University of Cambridge
The p.T1685I pathogenic mutation (also known as c.5054C>T), located in coding exon 15 of the BRCA1 gene, results from a C to T substitution at nucleotide position 5054. The threonine at codon 1685 is replaced by isoleucine, an amino acid with similar properties. This alteration has been identified in an individual diagnosed with ovarian cancer (Alhuqail AJ et al. Breast Cancer Res Treat, 2018 Apr;168:695-702). This alteration was also identified in a large, worldwide study of BRCA1/2 mutation positive families (Rebbeck TR et al. Hum Mutat, 2018 05;39:593-620). Multiple functional studies have found this variant to be non-functional including a phosphopeptide binding assay, a specificity assay, a protease sensitivity assay and a haploid cell survival assay (Lee MS et al. Cancer Res. 2010 Jun;70(12):4880-90; Petitalot A et al. Mol Cancer Res, 2019 01;17:54-69; Findlay GM et al. Nature, 2018 10;562:217-222). Another alteration at the same codon, p.T1685A (c.5053A>G), has been identified in a large, worldwide study of BRCA1/2 mutation positive families (Rebbeck TR et al. Hum Mutat, 2018 05;39:593-620). Additionally, multiple functional studies have found this variant to be non-functional including a phosphopeptide binding assay; a binding specificity assay; a protease sensitivity assay; a homology-directed DNA repair assay, and a haploid cell survival assay (Lee MS et al. Cancer Res. 2010 Jun;70(12):4880-90; Petitalot A et al. Mol Cancer Res, 2019 01;17:54-69; Findlay GM et al. Nature, 2018 10;562:217-222). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). Based on the supporting evidence, this alteration is interpreted as a disease-causing mutation. -
Hereditary breast ovarian cancer syndrome Pathogenic:1
Pathogenic, criteria provided, single submitter
clinical testing
Labcorp Genetics (formerly Invitae), Labcorp
Aug 22, 2023
Experimental studies have shown that this missense change affects BRCA1 function (PMID: 20516115, 30209399). Advanced modeling performed at Invitae incorporating data from internal and/or published experimental studies (PMID: 30209399) indicates that this missense variant is expected to disrupt BRCA1 function. ClinVar contains an entry for this variant (Variation ID: 55365). This missense change has been observed in individual(s) with ovarian cancer (PMID: 26689913, 29297111). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces threonine, which is neutral and polar, with isoleucine, which is neutral and non-polar, at codon 1685 of the BRCA1 protein (p.Thr1685Ile). This variant disrupts the p.Thr1685Ala amino acid residue in BRCA1. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 17924331, 20516115, 21990134, 27272900). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -