Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2
The NM_007294.4(BRCA1):c.69G>C(p.Glu23Asp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. E23E) has been classified as Likely benign.
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
Ambry Genetics
Jun 28, 2015
The p.E23D variant (also known as c.69G>C or 188G>C), located in coding exon 1 of the BRCA1 gene, results from a G to C substitution at nucleotide position 69. The glutamic acid at codon 23 is replaced by aspartic acid, an amino acid with highly similar properties. This variant was not reported in population based cohorts in the following databases: Database of Single Nucleotide Polymorphisms (dbSNP), NHLBI Exome Sequencing Project (ESP), and 1000 Genomes Project. In the ESP, this variant was not observed in 6502 samples (13004 alleles) with coverage of 6502 at this position. To date, this alteration has been detected with an allele frequency of approximately 0.001% (greater than 150000 alleles tested) in our clinical cohort. 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 p.E23D remains unclear. -
Hereditary breast ovarian cancer syndrome Uncertain:1
Uncertain significance, criteria provided, single submitter
clinical testing
Labcorp Genetics (formerly Invitae), Labcorp
Apr 24, 2016
This variant is not present in population databases (ExAC no frequency). This variant has been reported in individuals/families affected with breast and/or ovarian cancer (PMID: 21918854). In summary, this variant is a rare missense change with uncertain impact on protein function. While it is absent from the population and reported in affected individuals, the available evidence is currently insufficient to determine its role in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C15"). This sequence change replaces glutamic acid with aspartic acid at codon 23 of the BRCA1 protein (p.Glu23Asp). The glutamic acid residue is highly conserved and there is a small physicochemical difference between glutamic acid and aspartic acid. -
Breast-ovarian cancer, familial, susceptibility to, 1 Other:1
Gain of ubiquitination at K20 (P = 0.0737);Gain of ubiquitination at K20 (P = 0.0737);Gain of ubiquitination at K20 (P = 0.0737);Gain of ubiquitination at K20 (P = 0.0737);Gain of ubiquitination at K20 (P = 0.0737);Gain of ubiquitination at K20 (P = 0.0737);Gain of ubiquitination at K20 (P = 0.0737);Gain of ubiquitination at K20 (P = 0.0737);Gain of ubiquitination at K20 (P = 0.0737);Gain of ubiquitination at K20 (P = 0.0737);Gain of ubiquitination at K20 (P = 0.0737);Gain of ubiquitination at K20 (P = 0.0737);Gain of ubiquitination at K20 (P = 0.0737);Gain of ubiquitination at K20 (P = 0.0737);