rs80359045
Variant summary
Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PM2PP3_StrongPP5_Very_Strong
The NM_000059.4(BRCA2):c.8063T>C(p.Leu2688Pro) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000124 in 1,614,060 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★).
Frequency
Consequence
NM_000059.4 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Pathogenic. Variant got 14 ACMG points.
Transcripts
RefSeq
Ensembl
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
---|---|---|---|---|---|---|---|---|---|---|
BRCA2 | ENST00000380152.8 | c.8063T>C | p.Leu2688Pro | missense_variant | Exon 18 of 27 | 5 | NM_000059.4 | ENSP00000369497.3 | ||
BRCA2 | ENST00000530893.7 | c.7694T>C | p.Leu2565Pro | missense_variant | Exon 18 of 27 | 1 | ENSP00000499438.2 | |||
BRCA2 | ENST00000614259.2 | n.*121T>C | non_coding_transcript_exon_variant | Exon 17 of 26 | 2 | ENSP00000506251.1 | ||||
BRCA2 | ENST00000614259 | n.*121T>C | 3_prime_UTR_variant | Exon 17 of 25 | 2 | ENSP00000506251.1 |
Frequencies
GnomAD3 genomes AF: 0.00000657 AC: 1AN: 152224Hom.: 0 Cov.: 32
GnomAD4 exome AF: 6.84e-7 AC: 1AN: 1461836Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1AN XY: 727216
GnomAD4 genome AF: 0.00000657 AC: 1AN: 152224Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0AN XY: 74370
ClinVar
Submissions by phenotype
Hereditary breast ovarian cancer syndrome Pathogenic:3
Variant summary: BRCA2 c.8063T>C (p.Leu2688Pro) results in a non-conservative amino acid change located in the BRCA2, OB1 domain (IPR015187) of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 251256 control chromosomes. c.8063T>C has been reported in the literature in individuals from at-least one family affected with Hereditary Breast And Ovarian Cancer although the exact number of case counts have not been specified (example, Guidugli_2013). These data do not allow any conclusion about variant significance. Several publications report experimental evidence evaluating an impact on protein function. The most pronounced variant effect results in a loss of ability of BRCA2 to interact with the small (70-residues) DSS1 peptide, which appears to be crucial for the maintenance of its stability and correct conformation for the repair of DNA double stranded breaks (DSB's) by homologous recombination (HR) and the formation of DNA damage induced RAD51 foci (Caleca_2019). Consistently, other studies report a corresponding loss of HDR activity (example, Guidugli_2013 and Hart_2019). Five clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as pathogenic (n=1)/likely pathogenic (n=4). Based on the evidence outlined above, the variant was classified as likely pathogenic. -
This sequence change replaces leucine, which is neutral and non-polar, with proline, which is neutral and non-polar, at codon 2688 of the BRCA2 protein (p.Leu2688Pro). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with clinical features of BRCA2-related conditions (PMID: 10923033). ClinVar contains an entry for this variant (Variation ID: 38137). Invitae Evidence Modeling incorporating data from in vitro experimental studies (PMID: 33609447) indicates that this missense variant is expected to disrupt BRCA2 function with a positive predictive value of 95%. Experimental studies have shown that this missense change affects BRCA2 function (PMID: 23108138, 29394989, 30696104, 32444794, 33609447, 33964450). In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -
Data used in classification. The variant was observed in 2 independent UK families undergoing clinical diagnostic testing of BRCA1/BRCA2 for HBOC, the denominator of which dataset of clinical testing was 16,600. Case control comparison against ethnically matched population data (2/16,600 in familial cases against 0/63,369 GNOMAD NFE controls) 2-sided Fishers exact: pexact= 0.043 (PS4). The variant is absent in the remainder of the GNOMAD populations (75,263 individuals). (PM2). Predicted deleterious on AlignGVGD, SIFT, Polyphen2 HumVar (PP3). Segregation demonstrated in one UK family, N<1/16 (PP1_mod). P>0.99 on HR assay as detailed in Guidugli et al 2012 (Couch laboratory), which has demonstrated full validation against genetic epidemiological data of clinical pathogicity (PS3). Classified as pathogenic by Ambry and Quest Diagnostics (PP5). Data not used in classification. An additional 2 families have been identified in the UK (not included in the previous dataset).There are 5 additional reports of this variant on ClinVar. -
not provided Pathogenic:2
Published functional studies demonstrate a damaging effect: decreased homology-directed repair activity, protein binding, and sensitivity to PARP inhibitors (Guidugli 2013, Guidugli 2018, Mesman 2018, Caleca 2019, Hart 2019, Ikegami 2020, Richardson 2021); Multifactorial studies suggest this variant is likely associated with breast and ovarian cancer (Lindor 20012); Not observed in large population cohorts (Lek 2016); In silico analysis supports that this missense variant does not alter protein structure/function; Also known as 8291T>C; This variant is associated with the following publications: (PMID: 29884841, 23108138, 29394989, 29988080, 30696104, 32444794, 33609447, 21990134, 12228710, 32170000, 32042831, 31569370, 20167696, 19043619, 24323938) -
In the published literature, the variant has been reported to be defective in homology-directed DNA repair (PMID: 23108138 (2013), 29394989 (2018)). Additionally, it did not complement mouse embryonic cell lines deficient in BRCA2 (PMID: 29988080 (2018)). Therefore, the variant is classified as pathogenic. -
Hereditary cancer-predisposing syndrome Pathogenic:2
This missense variant replaces leucine with proline at codon 2688 of the BRCA2 protein. Computational prediction suggests that this variant may have deleterious impact on protein structure and function (internally defined REVEL score threshold >= 0.7, PMID: 27666373). Splice site prediction tools suggest that this variant may not impact RNA splicing. Functional studies have shown that this variant is deficient in homology-mediated DNA repair and the complementation of BRCA2-deficient mouse embryonic stem cell (PMID: 23108138, 29988080). A multifactorial analysis reported family history odds of pathogenicity of 3.44 with posterior probability of pathogenicity of 0.95 (PMID: 23108138) and ClinVar report indicated the identification of this variant in affected pedigrees in the UK (RCV000045408.5). This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). Based on the available evidence, this variant is classified as Likely Pathogenic. -
The p.L2688P pathogenic mutation (also known as c.8063T>C), located in coding exon 17 of the BRCA2 gene, results from a T to C substitution at nucleotide position 8063. The leucine at codon 2688 is replaced by proline, an amino acid with similar properties. In one study utilizing a bioinformatics method that integrates information about protein sequence, conservation, and structure in a protein likelihood ratio, the effect of this alteration was predicted deleterious (Karchin R et al. Cancer Inform. 2008 Apr;6:203-16). This alteration has been predicted to be pathogenic using homology-directed DNA repair (HDR) functional assays (Guidugli L et al. Cancer Res. 2013 Jan;73:265-75; Guidugli L et al. Am. J. Hum. Genet. 2018 02;102:233-248; Hart SN et al. Genet. Med. 2019 01;21:71-80). This variant segregated with disease in multiple families (Ambry internal data). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Based on the supporting evidence, this alteration is interpreted as a disease-causing mutation. -
Breast-ovarian cancer, familial, susceptibility to, 2 Uncertain:2
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BRCA2-related cancer predisposition Pathogenic:1
This missense variant replaces leucine with proline at codon 2688 of the BRCA2 protein. Computational prediction suggests that this variant may have deleterious impact on protein structure and function (internally defined REVEL score threshold >= 0.7, PMID: 27666373). Splice site prediction tools suggest that this variant may not impact RNA splicing. Functional studies have shown that this variant is deficient in homology-mediated DNA repair and the complementation of BRCA2-deficient mouse embryonic stem cell (PMID: 23108138, 29988080). A multifactorial analysis reported family history odds of pathogenicity of 3.44 with posterior probability of pathogenicity of 0.95 (PMID: 23108138) and ClinVar report indicated the identification of this variant in affected pedigrees in the UK (RCV000045408.5). This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). Based on the available evidence, this variant is classified as Likely Pathogenic. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at