13-32332449-G-C
Variant summary
Our verdict is Likely benign. Variant got -3 ACMG points: 0P and 3B. BP4_ModerateBP6
The NM_000059.4(BRCA2):āc.971G>Cā(p.Arg324Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000402 in 1,591,946 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/19 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).
Frequency
Consequence
NM_000059.4 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Likely_benign. Variant got -3 ACMG points.
Transcripts
RefSeq
Ensembl
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
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BRCA2 | ENST00000380152.8 | c.971G>C | p.Arg324Thr | missense_variant | Exon 10 of 27 | 5 | NM_000059.4 | ENSP00000369497.3 | ||
BRCA2 | ENST00000530893.7 | c.602G>C | p.Arg201Thr | missense_variant | Exon 10 of 27 | 1 | ENSP00000499438.2 | |||
BRCA2 | ENST00000614259.2 | n.971G>C | non_coding_transcript_exon_variant | Exon 9 of 26 | 2 | ENSP00000506251.1 |
Frequencies
GnomAD3 genomes AF: 0.00000657 AC: 1AN: 152092Hom.: 0 Cov.: 32
GnomAD3 exomes AF: 0.0000215 AC: 5AN: 232690Hom.: 0 AF XY: 0.0000239 AC XY: 3AN XY: 125782
GnomAD4 exome AF: 0.0000438 AC: 63AN: 1439854Hom.: 0 Cov.: 31 AF XY: 0.0000447 AC XY: 32AN XY: 715590
GnomAD4 genome AF: 0.00000657 AC: 1AN: 152092Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1AN XY: 74294
ClinVar
Submissions by phenotype
Breast-ovarian cancer, familial, susceptibility to, 2 Uncertain:3Benign:1
This missense variant replaces arginine with threonine at codon 324 of the BRCA2 protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). Experimental functional studies have reported conflicting results for this variant. In one study, the variant was shown to result in increased radial chromosome formation, percentage of cells in G2/M, a partial rescue of cell viability following DNA damage treatment (PMID: 31721781). However, another study reported no sensitivity to PARP inhibitors or carboplatin in cell viability assays (PMID: 32444794). This variant has been reported in individuals affected with breast cancer, ovarian cancer, and T-ALL (PMID: 11802209, 23269703, 31721781), the individual affected with ovarian cancer was also found to carry a pathogenic BRCA1 variant, which could explain the observed phenotype (PMID: 23269703). In a large breast cancer case-control meta analysis conducted by the BRIDGES consortium, this variant was reported in 2/60466 cases and 3/53461 unaffected controls (PMID: 33471991; Leiden Open Variation Database DB-ID BRCA2_002337). This variant has been identified in 5/232690 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -
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The following ACMG criteria is used: BP1_Strong -
Hereditary cancer-predisposing syndrome Uncertain:2Benign:1
This missense variant replaces arginine with threonine at codon 324 of the BRCA2 protein. Computational prediction suggests that this variant may not impact protein structure and function. A functional study has reported that this variant does not impact BRCA2 function in PARP inhibitors and carboplatin sensitivity assays (PMID: 32444794). This variant has been reported in individuals affected with breast cancer, ovarian cancer, and T-ALL (PMID: 11802209, 23269703, 31721781), the individual affected with ovarian cancer was also found to carry a pathogenic BRCA1 variant, which could explain the observed phenotype (PMID: 23269703). This variant has been detected in a breast cancer case-control meta-analysis in 2/60466 cases and 3/53461 unaffected individuals (PMID: 33471991; Leiden Open Variation Database DB-ID BRCA2_002337). A multifactorial analysis has reported a likelihood ratio for pathogenicity based on personal and family history of 0.493 from log(LR)=-0.306931227 (PMID: 31853058). This variant has been identified in 5/232690 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -
The p.R324T variant (also known as c.971G>C), located in coding exon 9 of the BRCA2 gene, results from a G to C substitution at nucleotide position 971. The arginine at codon 324 is replaced by threonine, an amino acid with similar properties. This variant was reported in a large hereditary breast and ovarian cancer family in which the proband was compound heterozygous for biallelic pathogenic mutations in BRCA1 (Domchek SM et al. Cancer Discov 2013; 3:399-405). This alteration was also detected in 1/989 unrelated individuals from a cohort of German breast/ovarian cancer families (Meindl A et al. Int. J. Cancer, 2002 Feb;97:472-80). This alteration was also identified in an individual with a family history of pancreatic cancer (Murali K et al. Hered Cancer Clin Pract, 2021 Aug;19:33). This amino acid position is poorly conserved on species alignment. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -
Missense variant in a coldspot region where missense variants are very unlikely to be pathogenic (PMID:31911673). -
not provided Uncertain:2
Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis, which includes protein predictors and evolutionary conservation, supports that this variant does not alter protein structure/function; Observed in individuals with personal and/or family history of breast, ovarian, and/or pancreatic cancer (Meindl et al., 2002; Domchek et al., 2013; Murali et al., 2021); This variant is associated with the following publications: (PMID: 25348012, 11802209, 29435075, 23269703, 34399810) -
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not specified Uncertain:1Benign:1
Variant summary: BRCA2 c.971G>C (p.Arg324Thr) results in a non-conservative amino acid change in the encoded protein sequence. Three of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 2.1e-05 in 232690 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.971G>C has been reported in the literature in individuals affected with Breast, Ovarian, and Pancreatic cancer (example: Domcheck_2013, Meindl_2002, Dorling_2021, Murali_2021). However, in one of the reported families the variant was found to co-occur with two separate pathogenic/likely pathogenic BRCA1 variants, c.2457delC and c.5207T>C. In addition, the variant seemed to not segregate with the disease in this family (Domchek_2013). At least two publications report experimental evidence evaluating an impact on protein function: One Fanconi-deficient rescue assay demonstrated that the variant causes partial loss of function (Pouliot_2019), and one BRCA2 null cell survival and proliferation assay following PARP inhibition demonstrated that the variant had normal function (Ikegami_2020). Six ClinVar submitters have assessed the variant since 2014: all submitters classified the variant as of uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -
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BRCA2-related disorder Uncertain:1
The BRCA2 c.971G>C variant is predicted to result in the amino acid substitution p.Arg324Thr. This variant was reported in an individual with family history of breast cancer (Meindl et al. 2002. PubMed ID: 11802209) and in an individual with family history of pancreatic cancer who had also variant of uncertain significance in BRCA1, p. Ala5Val (Murali et al. 2021. PubMed ID: 34399810). Functional studies show this variant has no effect on protein function (Ikegami et al. 2020. PubMed ID: 32444794) and intermediate effect on protein function (Pouliot et al. 2019. PubMed ID: 31721781). This variant is reported in 0.0046% of alleles in individuals of European (Non-Finnish) descent in gnomAD (http://gnomad.broadinstitute.org/variant/13-32906586-G-C). At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -
Hereditary breast ovarian cancer syndrome Uncertain:1
This sequence change replaces arginine, which is basic and polar, with threonine, which is neutral and polar, at codon 324 of the BRCA2 protein (p.Arg324Thr). This variant is present in population databases (rs397507435, gnomAD 0.005%). This missense change has been observed in individual(s) with breast cancer and/or family history of pancreatic cancer (PMID: 11802209, 34399810). ClinVar contains an entry for this variant (Variation ID: 38261). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is not expected to disrupt BRCA2 protein function with a negative predictive value of 95%. Experimental studies have shown that this missense change does not substantially affect BRCA2 function (PMID: 31721781, 32444794). In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at