rs876659382
Variant summary
Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2PP3
The NM_000059.4(BRCA2):c.8331+3A>C variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000248 in 1,609,992 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★★).
Frequency
Consequence
NM_000059.4 splice_region, intron
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Uncertain_significance. 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.8331+3A>C | splice_region_variant, intron_variant | Intron 18 of 26 | 5 | NM_000059.4 | ENSP00000369497.3 | |||
BRCA2 | ENST00000530893.7 | c.7962+3A>C | splice_region_variant, intron_variant | Intron 18 of 26 | 1 | ENSP00000499438.2 | ||||
BRCA2 | ENST00000614259.2 | n.*389+3A>C | splice_region_variant, intron_variant | Intron 17 of 25 | 2 | ENSP00000506251.1 |
Frequencies
GnomAD3 genomes AF: 0.0000197 AC: 3AN: 152188Hom.: 0 Cov.: 32
GnomAD4 exome AF: 6.86e-7 AC: 1AN: 1457804Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0AN XY: 725506
GnomAD4 genome AF: 0.0000197 AC: 3AN: 152188Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1AN XY: 74336
ClinVar
Submissions by phenotype
Breast-ovarian cancer, familial, susceptibility to, 2 Uncertain:2
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Hereditary cancer-predisposing syndrome Uncertain:2
The c.8331+3A>C intronic variant (also known as 8559+3A>C) results from an A to C substitution 3 nucleotides after coding exon 17 in the BRCA2 gene. This nucleotide position is well conserved in available vertebrate species. In silico splice site analysis predicts that this alteration will weaken the native splice donor site. RNA studies have demonstrated that this alteration results in an incomplete splice defect; the clinical impact of this abnormal splicing is unknown at this time (Ambry internal data; Casadei S et al. Proc. Natl. Acad. Sci. U.S.A. 2019 116(52): 26798–26807). Based on the available evidence, the clinical significance of this variant remains unclear. -
This variant causes an A to C nucleotide substitution at the +3 position of intron 18 of the BRCA2 gene. Splice site prediction tools predict that this variant may have a significant impact on RNA splicing. An RNA study has reported that this variant results in two aberrant mRNA transcripts with premature truncations in the coding sequence that are predicted to trigger nonsense-mediated decay, however, the extent of this splicing defect is partial and some full-length transcript is still produced (PMID: 31843900). This variant has not been reported in individuals affected with hereditary cancer in the literature. This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). Although there is a suspicion that this variant may be associated with disease, additional studies are necessary to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -
Hereditary breast ovarian cancer syndrome;C2675520:Breast-ovarian cancer, familial, susceptibility to, 2 Pathogenic:1
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not specified Uncertain:1
Variant summary: BRCA2 c.8331+3A>C alters a conserved nucleotide located close to a canonical splice site and therefore could affect mRNA splicing, leading to a significantly altered protein sequence. Several computational tools predict a significant impact on normal splicing: Three predict the variant weakens a 5 prime donor site. Two predict the variant abolishes a 5 prime splicing donor site. However, these predictions have yet to be confirmed by functional studies. The variant was absent in 245066 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. To our knowledge, no occurrence of c.8331+3A>C in individuals affected with Hereditary Breast and Ovarian Cancer and no experimental evidence demonstrating its impact on protein function have been reported. Three 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 uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -
Medulloblastoma;C0346153:Familial cancer of breast;C0376358:Malignant tumor of prostate;C1838457:Fanconi anemia complementation group D1;C2675520:Breast-ovarian cancer, familial, susceptibility to, 2;C2751641:Glioma susceptibility 3;C3150546:Pancreatic cancer, susceptibility to, 2;CN033288:Wilms tumor 1 Uncertain:1
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not provided Uncertain:1
Published functional studies are inconclusive: both wild type and aberrant transcript observed (Casadei et al., 2019); Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports a deleterious effect on splicing; Also known as BRCA2 8559+3A>C; This variant is associated with the following publications: (PMID: 31843900) -
Familial cancer of breast Uncertain:1
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Hereditary breast ovarian cancer syndrome Uncertain:1
This sequence change falls in intron 18 of the BRCA2 gene. It does not directly change the encoded amino acid sequence of the BRCA2 protein. It affects a nucleotide within the consensus splice site. This variant is not present in population databases (gnomAD no frequency). This variant has been observed in individual(s) with hereditary breast and/or ovarian cancer (PMID: 31843900). ClinVar contains an entry for this variant (Variation ID: 231812). Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Studies have shown that this variant is associated with inconclusive levels of altered splicing (internal data). 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