Our verdict is Uncertain significance. Variant got 1 ACMG points: 2P and 1B. PM2BP4
The NM_007294.4(BRCA1):c.3496G>C(p.Ala1166Pro) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,772 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 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]
ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Collection Method: clinical testing
The BRCA1 c.3496G>C; p.Ala1166Pro variant (rs745418679), to our knowledge, is not reported in the medical literature but is reported in ClinVar (Variation ID: 216663). This variant is found on a single chromosome in the Genome Aggregation Database (1/251294 alleles), indicating it is not a common polymorphism. The alanine at codon 1166 is moderately conserved, but computational analyses (SIFT: damaging, PolyPhen-2: benign) predict conflicting effects of this variant on protein structure/function. However, due to limited information, the clinical significance of the p.Ala1166Pro variant is uncertain at this time. -
Feb 16, 2021
GeneDx
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Collection Method: clinical testing
Not observed at a significant frequency in large population cohorts (Lek 2016); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Has not been previously published as pathogenic or benign to our knowledge; Also known as 3615G>C -
Review Status: criteria provided, single submitter
Collection Method: clinical testing
The p.A1166P variant (also known as c.3496G>C), located in coding exon 9 of the BRCA1 gene, results from a G to C substitution at nucleotide position 3496. The alanine at codon 1166 is replaced by proline, an amino acid with highly similar properties. This alteration was identified in a cohort of 524 Chinese breast cancer patients (Chen B et al. Aging (Albany NY), 2020 Feb;12:3140-3155). This amino acid position is not well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -
Mar 23, 2023
University of Washington Department of Laboratory Medicine, University of Washington
Significance: Likely benign
Review Status: criteria provided, single submitter
Collection Method: curation
Missense variant in a coldspot region where missense variants are very unlikely to be pathogenic (PMID:31911673). -
Hereditary breast ovarian cancer syndrome Uncertain:1
Jul 30, 2024
Labcorp Genetics (formerly Invitae), Labcorp
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Collection Method: clinical testing
This sequence change replaces alanine, which is neutral and non-polar, with proline, which is neutral and non-polar, at codon 1166 of the BRCA1 protein (p.Ala1166Pro). This variant is present in population databases (rs745418679, gnomAD 0.0009%). This variant has not been reported in the literature in individuals affected with BRCA1-related conditions. ClinVar contains an entry for this variant (Variation ID: 216663). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt BRCA1 protein function with a negative predictive value of 95%. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -