2-214752442-C-T
Variant summary
Our verdict is Uncertain significance. The variant received 1 ACMG points: 5P and 4B. PP3_StrongPP5BS2
The NM_000465.4(BARD1):c.1677+5G>A variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000761 in 1,446,056 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 Conflicting classifications of pathogenicity (no stars).
Frequency
Consequence
NM_000465.4 splice_region, intron
Scores
Clinical Significance
Conservation
Publications
- breast cancerInheritance: AD Classification: DEFINITIVE Submitted by: G2P
- hereditary breast carcinomaInheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), ClinGen
- familial ovarian cancerInheritance: AD Classification: LIMITED Submitted by: ClinGen
- hereditary nonpolyposis colon cancerInheritance: AD Classification: LIMITED Submitted by: ClinGen
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ACMG classification
Our verdict: Uncertain_significance. The variant received 1 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes Cov.: 32
GnomAD4 exome AF: 0.00000761 AC: 11AN: 1446056Hom.: 0 Cov.: 28 AF XY: 0.00000416 AC XY: 3AN XY: 720408 show subpopulations
Age Distribution
GnomAD4 genome Cov.: 32
ClinVar
Submissions by phenotype
Familial cancer of breast Pathogenic:2Uncertain:1
This sequence change falls in intron 7 of the BARD1 gene. It does not directly change the encoded amino acid sequence of the BARD1 protein. RNA analysis indicates that this variant induces altered splicing and may result in an absent or altered protein product. This variant is not present in population databases (gnomAD no frequency). This variant has been observed in individual(s) with breast cancer (PMID: 34326862). ClinVar contains an entry for this variant (Variation ID: 127718). Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Studies have shown that this variant results in skipping of exon 7, and produces a non-functional protein and/or introduces a premature termination codon (internal data). For these reasons, this variant has been classified as Pathogenic. -
This variant is considered likely pathogenic. mRNA analysis has demonstrated abnormal mRNA splicing occurs [Myriad internal data]. -
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Hereditary cancer-predisposing syndrome Uncertain:2
The c.1677+5G>A intronic variant results from a G to A substitution 5 nucleotides after coding exon 7 in the BARD1 gene. This nucleotide position is highly conserved in available vertebrate species. In silico splice site analysis predicts that this alteration will weaken the native splice donor site. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -
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not provided Pathogenic:1
Intronic +5 splice site variant in a gene for which loss of function is a known mechanism of disease, and splice predictors support a deleterious effect; Not observed at significant frequency in large population cohorts (gnomAD); Has not been previously published as pathogenic or benign to our knowledge -
Malignant tumor of breast Pathogenic:1
Variant summary: BARD1 c.1677+5G>A 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: Four predict the variant abolishes the canonial 5' splicing donor site. Internal RNA analysis provides experimental evidence that this variant affects mRNA splicing resulting in the skipping of exon 7 producing a non-functional protein and/or introducing a premature termination codon [r.1569_1677del (p.Asn524*), internal data]. Loss of Function (LOF) variants in BARD1 are an established mechanism of disease. The variant was absent in 251290 control chromosomes. c.1677+5G>A has been reported in the literature in at-least one individual affected with Breast Cancer (Bhai_2021). At-least one co-occurrence with another pathogenic variant(s) has been reported in this individual [CHEK2 c.1100delC, p.(Thr367Metfs*15)]. Although, this co-occurrence is not weighted in the context of this evaluation. The following publications have been ascertained in the context of this evaluation (PMID: 34326862). ClinVar contains an entry for this variant (Variation ID: 127718). Based on the evidence outlined above, the variant was classified as pathogenic. -
not specified Uncertain:1
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BARD1-related cancer predisposition Uncertain:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at