Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PVS1_StrongPM2PP5_Very_Strong
The NM_007294.4(BRCA1):c.5536C>T(p.Gln1846*) variant causes a stop gained 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. Variant has been reported in ClinVar as Pathogenic (★★★).
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 Pathogenic. Variant got 14 ACMG points.
PVS1
Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. There are 13 pathogenic variants in the truncated region.
PM2
Very rare variant in population databases, with high coverage;
PP5
Variant 17-43045734-G-A is Pathogenic according to our data. Variant chr17-43045734-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 55620.Status of the report is reviewed_by_expert_panel, 3 stars. Variant chr17-43045734-G-A is described in Lovd as [Pathogenic]. Variant chr17-43045734-G-A is described in Lovd as [Pathogenic].
Breast-ovarian cancer, familial, susceptibility to, 1 Pathogenic:5Other:1
Oct 02, 2015
Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA), c/o University of Cambridge
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing
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Feb 20, 2004
Breast Cancer Information Core (BIC) (BRCA1)
Significance: Pathogenic
Review Status: no assertion criteria provided
Collection Method: clinical testing
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Sep 08, 2016
Evidence-based Network for the Interpretation of Germline Mutant Alleles (ENIGMA)
Significance: Pathogenic
Review Status: reviewed by expert panel
Collection Method: curation
Variant allele predicted to encode a truncated non-functional protein. -
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Molecular Endocrinology Laboratory, Christian Medical College
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing
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Brotman Baty Institute, University of Washington
Significance: not provided
Review Status: no classification provided
Collection Method: in vitro
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Apr 24, 2014
Counsyl
Significance: Likely pathogenic
Review Status: criteria provided, single submitter
Collection Method: literature only
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Hereditary breast ovarian cancer syndrome Pathogenic:2
May 18, 2023
Women's Health and Genetics/Laboratory Corporation of America, LabCorp
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing
Variant summary: BRCA1 c.5536C>T (p.Gln1846X) results in a premature termination codon, while it is not expected to exhibit nonsense mediated decay, it is predicted to cause a truncation of the encoded protein, a commonly known mechanism for disease. The variant was absent in 250938 control chromosomes (gnomAD). c.5536C>T has been reported in the literature in multiple individuals from at least seven different families affected with Hereditary Breast And Ovarian Cancer Syndrome (e.g Kroiss_2005, Rebbeck_2018). These data indicate that the variant is very likely to be associated with disease. At least one functional study reports experimental evidence evaluating an impact on protein function and showed that this variant was non-functional with respect to homology directed repair (HDR) activity (e.g. Findlay_2018). The following publications have been ascertained in the context of this evaluation (PMID: 30209399, 16287141, 29446198). Four submitters, including an expert panel (ENIGMA) have provided clinical-significance assessments for this variant to ClinVar after 2014 and all classified the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -
Oct 03, 2022
Labcorp Genetics (formerly Invitae), Labcorp
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing
For these reasons, this variant has been classified as Pathogenic. This variant disrupts a region of the BRCA1 protein in which other variant(s) (p.Tyr1853*) have been determined to be pathogenic (PMID: 10811118, 20104584, 21922593, 24504028). This suggests that this is a clinically significant region of the protein, and that variants that disrupt it are likely to be disease-causing. Experimental studies have shown that this premature translational stop signal affects BRCA1 function (PMID: 30209399). Algorithms developed to predict the effect of variants on protein structure and function are not available or were not evaluated for this variant. ClinVar contains an entry for this variant (Variation ID: 55620). This premature translational stop signal has been observed in individual(s) with hereditary breast and/or ovarian cancer (PMID: 16287141, 29446198, 30702160). This variant is not present in population databases (gnomAD no frequency). This sequence change creates a premature translational stop signal (p.Gln1846*) in the BRCA1 gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 18 amino acid(s) of the BRCA1 protein. -
Review Status: criteria provided, single submitter
Collection Method: clinical testing
The p.Q1846* pathogenic mutation (also known as c.5536C>T), located in coding exon 22 of the BRCA1 gene, results from a C to T substitution at nucleotide position 5536. This changes the amino acid from a glutamine to a stop codon within coding exon 22. This alteration occurs at the 3' terminus of theBRCA1 gene, is not expected to trigger nonsense-mediated mRNA decay, and only impacts the last 18 amino acids of the protein. However, premature stop codons are typically deleterious in nature and the impacted region is critical for protein function (Ambry internal data). This mutation has been reported in individuals with hereditary breast and/or ovarian cancer (Kroiss R et al. Hum. Mutat., 2005 Dec;26:583-9; Cavallone L et al. Fam. Cancer, 2010 Dec;9:507-17; Kuo WH et al. J. Hum. Genet., 2012 Feb;57:130-8). Based on the supporting evidence, this alteration is interpreted as a disease-causing mutation. -