Our verdict is Likely benign. Variant got -3 ACMG points: 2P and 5B. PM2BP4_StrongBP6
The NM_007294.4(BRCA1):c.4675+20A>G variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000031 in 1,613,238 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]
Verdict is Likely_benign. Variant got -3 ACMG points.
PM2
Very rare variant in population databases, with high coverage;
BP4
Computational evidence support a benign effect (BayesDel_noAF=-0.84).
BP6
Variant 17-43074311-T-C is Benign according to our data. Variant chr17-43074311-T-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 383202.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=3, Uncertain_significance=1}. Variant chr17-43074311-T-C is described in Lovd as [Likely_benign].
Likely benign, criteria provided, single submitter
clinical testing
GeneDx
Dec 22, 2017
This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -
Uncertain significance, criteria provided, single submitter
clinical testing
Women's Health and Genetics/Laboratory Corporation of America, LabCorp
Oct 14, 2019
Variant summary: BRCA1 c.4675+20A>G alters a non-conserved nucleotide located close to a canonical splice site and therefore could affect mRNA splicing, leading to a significantly altered protein sequence. 4/5 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 250912 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. To our knowledge, no occurrence of c.4675+20A>G in individuals affected with Hereditary Breast and Ovarian Cancer and no experimental evidence demonstrating its impact on protein function have been reported. Three ClinVar submissions (evaluation after 2014) cite the variant as likely benign. Based on the evidence outlined above, the variant was classified as VUS-possibly benign. -
Hereditary cancer-predisposing syndrome Benign:1
Likely benign, criteria provided, single submitter
clinical testing
Color Diagnostics, LLC DBA Color Health
Nov 18, 2016
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Hereditary breast ovarian cancer syndrome Benign:1
Likely benign, criteria provided, single submitter