17-43093054-G-T
Variant summary
Our verdict is Benign. Variant got -9 ACMG points: 0P and 9B. BP4BP6_Very_Strong
The NM_007294.4(BRCA1):c.2477C>A(p.Thr826Lys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000341 in 1,613,812 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Benign (★★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. T826A) has been classified as Likely benign.
Frequency
Consequence
NM_007294.4 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Benign. Variant got -9 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.000204 AC: 31AN: 152130Hom.: 0 Cov.: 32
GnomAD3 exomes AF: 0.000179 AC: 45AN: 250902Hom.: 0 AF XY: 0.000162 AC XY: 22AN XY: 135618
GnomAD4 exome AF: 0.000355 AC: 519AN: 1461564Hom.: 1 Cov.: 40 AF XY: 0.000329 AC XY: 239AN XY: 727110
GnomAD4 genome AF: 0.000204 AC: 31AN: 152248Hom.: 0 Cov.: 32 AF XY: 0.000161 AC XY: 12AN XY: 74434
ClinVar
Submissions by phenotype
Breast-ovarian cancer, familial, susceptibility to, 1 Uncertain:2Benign:6
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The BRCA1 p.Thr826Lys variant was identified in 12 of 6080 proband chromosomes (frequency: 0.002) from individuals or families with breast or ovarian cancer and was not identified in 372 control chromosomes from healthy individuals (Simard 2007, Capanu 2011, Tonin 1998, Palomba 2009, Klemp 2000, Dean 2015). The variant was identified in dbSNP (rs28897683) as “with other allele”, ClinVar (classified as benign by ENIGMA expert panel in 2015, Invitae, Ambry Genetics, Gene Dx and 6 other submitters; as likely benign by Counsyl, Color and 2 other submitters; and as uncertain significance by BIC and 3 other submitters), LOVD 3.0 (observed 17x) and UMD-LSDB (observed 33x). The variant was identified in control databases in 52 of 276616 chromosomes at a frequency of 0.0002 (Genome Aggregation Database Feb 27, 2017). The variant was observed in the following populations: African in 4 of 24,028 chromosomes (freq: 0.0002), Latino in 8 of 34,412 chromosomes (freq: 0.0002) and European in 40 of 126,296 chromosomes (freq: 0.0003), while the variant was not observed in the Other, Ashkenazi Jewish, East Asian, Finnish, or South Asian populations. The variant was observed in the UMD-LSDB database in 3 cases with co-occurring pathogenic variants: BRCA1 c.3669del (p.Cys1225Alafs*10), BRCA1 c.4251_4252del (p.Leu1418Argfs*9), and BRCA2 c.6359C>G (p.Ser2120*). In a complementation assay in BRCA1-deficient mouse embryonic stem cells, the variant was demonstrated to have no observed effect on cell proliferation and sensitivity to cisplatin, indicating the variant protein activity was sufficient to complement the BRCA1-null cells (Bouwman 2013). The p.Thr826 residue is conserved in mammals but not in more distantly related organisms and four out of five computational analyses (PolyPhen-2, SIFT, AlignGVGD, BLOSUM, MutationTaster) do not suggest a high likelihood of impact to the protein; this information is not predictive enough to rule out pathogenicity. The variant occurs outside of the splicing consensus sequence and in silico or computational prediction software programs (SpliceSiteFinder, MaxEntScan, NNSPLICE, GeneSplicer) do not predict a difference in splicing. In summary, based on the above information, the clinical significance of this variant cannot be determined with certainty at this time although we would lean towards a more benign role for this variant. This variant is classified as likely benign. -
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This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). Publications were found based on this search. However, the evidence from the literature, in combination with allele frequency data from public databases where available, was not sufficient to rule this variant in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance. -
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IARC class based on posterior probability from multifactorial likelihood analysis, thresholds for class as per Plon et al. 2008 (PMID: 18951446). Class 1 based on posterior probability = 0.00000000203 -
not specified Benign:8
The p.Thr826Lys variant in BRCA1 is classified as likely benign because it has been identified in 0.03% (40/128816) of European chromosomes by gnomAD (http://gnomad.broadinstitute.org). This variant was classified as Benign on August 10, 2015 by the ClinGen-approved ENIGMA expert panel (Variation ID 37473). Computational prediction tools and conservation analyses suggest that this variant may not impact the protein, though this information is not predictive enough to rule out pathogenicity. ACMG/AMP Criteria applied: BS1, BP4. -
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. -
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not provided Benign:4
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BRCA1: BS3:Supporting, BS2 -
Hereditary breast ovarian cancer syndrome Benign:4
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The BRCA1 c.2477C>A (p.Thr826Lys) missense change has a maximum subpopulation frequency of 0.031% in gnomAD v2.1.1 (https://gnomad.broadinstitute.org/variant/17-41245071-G-T). In silico tools are not in agreement about the effect of this variant on protein function, however in vitro functional studies have shown that this variant results in an activity comparable to the wild type in cell proliferation and cisplatin sensitivity assays (BS3; PMID: 23867111). This variant has been reported in four women older than 70 years of age who have never had cancer (BS2_supporting; https://whi.color.com/variant/17-41245071-G-T). In addition, this variant has been reported to co-occur with pathogenic variants in BRCA1 and BRCA2 (BP2; UMD database). In summary, this variant meets criteria to be classified as likely benign based on the ACMG/AMP criteria: BS3, BS2_supporting, BP2. -
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Hereditary cancer-predisposing syndrome Benign:3
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This alteration is classified as benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -
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Breast neoplasm Uncertain:1
Low GERP score may suggest that this variant may belong in a lower pathogenicity class -
Breast and/or ovarian cancer Benign:1
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BRCA1-related cancer predisposition Benign:1
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BRCA1-related disorder Benign:1
This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at