The variant received 22 classification points (ACMG Germline Pathogenicity v2019). PVS1PS1PS3PM2PP5_Strong
The NM_001407853.1(BRCA1):c.2T>C (p.Met1?) variant causes a start lost, splice region change involving the alteration of a non-conserved nucleotide. Note: NM_001407853.1 is not a MANE Select or MANE Plus Clinical transcript for BRCA1; the reported annotation may differ from that of the MANE-designated reference transcript for this gene. This is a canonical splice-site variant (loss-of-function). The variant is absent from the gnomAD population database at sites with sufficient sequencing coverage. In-silico predictor (REVEL) classifies this variant as likely damaging/oncogenic. Splicing prediction tools (SpliceAI) predict no significant impact on normal splicing. Variant has been reported in ClinVar as Pathogenic/Likely Pathogenic (★★). ClinVar reports functional evidence for this variant: "SCV000185680: One functional study found that this nucleotide substitution is non-functional in a high-throughput, genome editing, haploid cell survival assay (Findlay GM et al. Nature, 2018 10;562:217-222). In addition, other functional studies have shown that p.C64R adversely affects the BRCA1/BARD1 complex formation, and leads to increased sensitivity to ionizing radiation and chromosomal instability (Caleca L et al. PLoS ONE, 2014 Feb;9:e86924" and additional evidence is available in ClinVar. A different missense at the same amino acid position has been reported as Pathogenic/Likely Pathogenic in ClinVar: p.C64G: Pathogenic (ClinVar VariationId 17660, 2 stars) Other variants at the same amino acid position have been reported in ClinVar (not pathogenic): p.C64= (synonymous): unknown significance (ClinVar VariationId 867931); p.C64F: unknown significance (ClinVar VariationId 867930)
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]
BRCA1 Gene-Disease associations (from GenCC):
BRCA1-related cancer predisposition
Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
breast-ovarian cancer, familial, susceptibility to, 1
Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae), Ambry Genetics
new If you want to explore the variant's impact on the transcript NM_001407853.1, check out the Mutation Effect Viewer. This is especially useful for frameshift variants or if you want to visualize the effect of exon loss / intron retention.
Classification according to ACMG Germline Pathogenicity v2019
Our verdict: Pathogenic. The variant received 22 points.
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Criterion Code & Title / Strength
Strength
Rationale / Clinical Context
PVS1Null variant in LOF gene
Start-lost with downstream start: ≥7 pathogenic between starts — very strong ; Start codon lost (exon 4 of 24); downstream rescue start codon present, but 96 pathogenic variants between start codons indicate significant functional impact.
PS1Same amino acid change as known pathogenic
Different start-lost, ≥3-star ClinVar pathogenic — strong (PS1); ClinVar contains 7 P/LP entries with the start-lost variant at the same initiation codon (highest review level: 3 stars).
PS3Functional studies show damaging effect
Well-established functional study supports damaging effect (PS3); SCV000185680: One functional study found that this nucleotide substitution is non-functional in a high-throughput, genome editing, haploid cell survival assay (Findlay GM et al. Nature, 2018 10;562:217-222). In addition, other functional studies have shown that p.C64R adversely affects the BRCA1/BARD1 complex formation, and leads to increased sensitivity to ionizing radiation and chromosomal instability (Caleca L et al. PLoS ONE, 2014 Feb;9:e86924; Cochran RL et al. Oncotarget, 2015 Sep;6:25240-51).; SCV000688353: Functional studies have reported that this variant impacts BRCA1 function in homology-directed repair, BARD1 binding, ubiquitin E3 ligase, a haploid cell proliferation, sensitivity to ionizing radiation and PARP inhibitors and chromosomal instability assays (PMID: 24516540, 25823446, 26246475, 28398198, 30209399).; SCV001365790: in vitro functional studies support an impact on protein function (Willems 2009, Caleca 2014, Cochran 2015, Findlay 2018).; SCV001582761: Experimental studies have shown that this missense change affects BRCA1 function (PMID: 19287957, 24516540, 25823446).; SCV001469985: Assessment of experimental evidence suggests this variant results in abnormal protein function (PMIDs: 24516540 (2014), 25823446 (2015), 26246475 (2015)).; SCV007107058: PS3
PM2Absent/extremely low in population databases
Absent from gnomAD (AD/XL gene) — PM2; Absent from gnomAD at well-covered site (MOI: AD+AR) (threshold 0.0001) — PM2 moderate.
Automated classification analysis was done for transcript: NM_001407853.1. You can select a different transcript below to see updated classification assignments.
MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.
MaveDB functional evidence
MaveDB is a public repository of laboratory assays that test the effect of thousands of variants at once — treat this as supporting research data and interpret it with great caution; it is not a clinical classification.
1 abnormal
3 no calibration
4 assays found for this variant.
Clinical calibration: 1 functionally abnormal (PS3), 0 functionally normal (BS3).
Meta-analysis of urn:mavedb:00000097-a-1, urn:mavedb:00000097-b-1, urn:mavedb:00000097-c-1, urn:mavedb:00000097-d-1, urn:mavedb:00000097-e-1 and 21 others