Our verdict is Uncertain significance. Variant got 5 ACMG points: 6P and 1B. PVS1_ModeratePM2PP3_ModerateBP6
The ENST00000478531.6(BRCA1):c.784+1G>T variant causes a splice donor change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 1/1 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).
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 Uncertain_significance. Variant got 5 ACMG points.
PVS1
Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.05087719 fraction of the gene. Cryptic splice site detected, with MaxEntScore 8, offset of -1, new splice context is: cagGTtagt. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.
PM2
Very rare variant in population databases, with high coverage;
PP3
Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
BP6
Variant 17-43094743-C-A is Benign according to our data. Variant chr17-43094743-C-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 55701.We mark this variant Likely_benign, oryginal submissions are: {not_provided=1, Likely_benign=1, Uncertain_significance=2}.
Uncertain significance, criteria provided, single submitter
clinical testing
Ambry Genetics
Feb 07, 2023
The p.G263V variant (also known as c.788G>T), located in coding exon 9 of the BRCA1 gene, results from a G to T substitution at nucleotide position 788. The glycine at codon 263 is replaced by valine, an amino acid with dissimilar properties. This amino acid position is not well conserved in available vertebrate species. In silico splice site analysis predicts that this alteration will result in the creation or strengthening of a novel splice donor site; however, direct evidence is insufficient at this time (Ambry internal data). In addition, as a missense substitution this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -
Likely benign, criteria provided, single submitter
curation
University of Washington Department of Laboratory Medicine, University of Washington
Mar 23, 2023
Missense variant in a coldspot region where missense variants are very unlikely to be pathogenic (PMID:31911673). -
Uncertain significance, criteria provided, single submitter
clinical testing
Color Diagnostics, LLC DBA Color Health
Aug 19, 2020
This missense variant replaces glycine with valine at codon 263 of the BRCA1 protein. Computational prediction is inconclusive regarding the impact of this variant on protein structure and function (internally defined REVEL score threshold 0.5 < inconclusive < 0.7, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has not been reported in individuals affected with hereditary cancer in the literature. This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -
Familial cancer of breast Other:1
not provided, no classification provided
literature only
ClinVar Staff, National Center for Biotechnology Information (NCBI)