Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2
The NM_007294.4(BRCA1):c.550T>A(p.Ser184Thr) variant causes a missense, splice region change. The variant allele was found at a frequency of 0.00000342 in 1,460,974 control chromosomes in the GnomAD database, with no homozygous occurrence. 1/1 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. S184F) has been classified as Uncertain significance.
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]
Uncertain significance, criteria provided, single submitter
clinical testing
Color Diagnostics, LLC DBA Color Health
Oct 13, 2020
This missense variant replaces serine with threonine at codon 184 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 been reported in one individual affected with breast cancer (PMID: 21918854). This variant has been identified in 1/250928 chromosomes 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. -
Uncertain significance, criteria provided, single submitter
clinical testing
Ambry Genetics
Jun 09, 2023
The p.S184T variant (also known as c.550T>A), located in coding exon 7 of the BRCA1 gene, results from a T to A substitution at nucleotide position 550. The serine at codon 184 is replaced by threonine, an amino acid with similar properties. This alteration was detected in an individual diagnosed with breast cancer (Keshavarzi F et al. Fam. Cancer. 2012 Mar;11:57-67). This amino acid position is highly 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. -
not specified Uncertain:1
Uncertain significance, criteria provided, single submitter
clinical testing
Women's Health and Genetics/Laboratory Corporation of America, LabCorp
Jul 17, 2023
Variant summary: BRCA1 c.550T>A (p.Ser184Thr) results in a conservative amino acid change in the encoded protein sequence. Three of five in-silico tools predict a damaging effect of the variant on protein function. Computational tools predict no significant impact on normal splicing. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 4e-06 in 250928 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.550T>A has been reported in the literature in at least one possible individual affected with Breast Cancer (Keshavarzi_2012). This report does not provide unequivocal conclusions about association of the variant with Hereditary Breast And Ovarian Cancer Syndrome. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publication has been ascertained in the context of this evaluation (PMID: 21918854). Four ClinVar submitters have assessed the variant since 2014: all submitters classified the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -
Breast-ovarian cancer, familial, susceptibility to, 1 Uncertain:1
Uncertain significance, criteria provided, single submitter
clinical testing
All of Us Research Program, National Institutes of Health
Dec 01, 2023
This missense variant replaces serine with threonine at codon 184 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 been reported in one individual affected with breast cancer (PMID: 21918854). This variant has been identified in 1/250928 chromosomes 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. -
not provided Uncertain:1
Uncertain significance, criteria provided, single submitter
clinical testing
GeneDx
Jul 07, 2016
This variant is denoted BRCA1 c.550T>A at the cDNA level, p.Ser184Thr (S184T) at the protein level, and results in the change of a Serine to a Threonine (TCT>ACT). Using alternate nomenclature, this variant would be defined as BRCA1 669T>A. This variant has been observed in at least one individual with early onset breast cancer (Keshavarzi 2012). BRCA1 Ser184Thr was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, suggesting it is not a common benign variant in these populations. Since Serine and Threonine share similar properties, this is considered a conservative amino acid substitution. BRCA1 Ser184Thr occurs at a position that is conserved across species and is located in the binding domain of BRD7 and MB2 (myc binding) (Wang 1998, Harte 2010). In silico analyses are inconsistent regarding the effect this variant may have on protein structure and function. Based on currently available evidence, it is unclear whether BRCA1 Ser184Thr is a pathogenic or benign variant. We consider it to be a variant of uncertain significance. -
Hereditary breast ovarian cancer syndrome Uncertain:1
Uncertain significance, criteria provided, single submitter
clinical testing
Labcorp Genetics (formerly Invitae), Labcorp
Dec 24, 2023
This sequence change replaces serine, which is neutral and polar, with threonine, which is neutral and polar, at codon 184 of the BRCA1 protein (p.Ser184Thr). This variant is present in population databases (no rsID available, gnomAD 0.0009%). This missense change has been observed in individual(s) with breast cancer (PMID: 21918854). ClinVar contains an entry for this variant (Variation ID: 421643). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. 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. -
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