rs869312788
Variant summary
Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM2PP3_StrongPP5
The NM_000051.4(ATM):c.7788+3A>G variant causes a splice region, intron change. The variant was absent in control chromosomes in GnomAD project. 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_000051.4 splice_region, intron
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Likely_pathogenic. Variant got 7 ACMG points.
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
---|---|---|---|---|---|---|---|---|
ATM | NM_000051.4 | c.7788+3A>G | splice_region_variant, intron_variant | Intron 52 of 62 | ENST00000675843.1 | NP_000042.3 |
Ensembl
Frequencies
GnomAD3 genomes Cov.: 32
GnomAD4 exome Cov.: 31
GnomAD4 genome Cov.: 32
ClinVar
Submissions by phenotype
Ataxia-telangiectasia syndrome Pathogenic:2
Variant summary: ATM c.7788+3A>G 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: One predicts the variant weakens a 5' donor site. One predicts the variant abolishes a 5' splicing donor site. Functional studies report that the variant resulted in aberrant splicing (PMID: 33011440, Internal data). The variant was absent in 250802 control chromosomes (gnomAD). c.7788+3A>G has been reported in the literature in at least an individual affected with Ataxia-Telangiectasia where it was seen in trans with a pathogenic variant (DeStefano_2016). The following publications have been ascertained in the context of this evaluation (PMID: 26845104, 33011440). ClinVar contains an entry for this variant (Variation ID: 420257). Based on the evidence outlined above, the variant was classified as pathogenic. -
This sequence change falls in intron 52 of the ATM gene. It does not directly change the encoded amino acid sequence of the ATM protein. RNA analysis indicates that this variant induces altered splicing and likely results in a shortened protein product. This variant is not present in population databases (gnomAD no frequency). This variant has been observed in individual(s) with ataxia-telangiectasia and/or breast cancer (PMID: 33011440; De Stefano et al. 2016. J Lab Med. 40(4): 255–261). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 420257). 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 52, but is expected to preserve the integrity of the reading-frame (PMID: 33011440; Invitae). This variant disrupts a region of the ATM protein in which other variant(s) (p.Arg2547_Ser2549del) have been determined to be pathogenic (PMID: 7792600, 8797579, 11382771, 12552559, 21787400, 22649200). This suggests that this is a clinically significant region of the protein, and that variants that disrupt it are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -
Hereditary cancer-predisposing syndrome Pathogenic:1Uncertain:1
The c.7788+3A>G intronic variant results from an A to G substitution 3 nucleotides after coding exon 51 in the ATM 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. In a study involving RNA extraction for RT-PCR and Sanger sequencing of 10 hereditary cancer genes, incomplete disruption of the natural splice site was observed for this alteration (Rofes P et al. J Mol Diagn, 2020 12;22:1453-1468). Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -
The c.7788+3A>G variant it is predicted to disrupt the donor splice site for intron 52. The skipping of exon 52 predicted by default would result in an in-frame deletion of 53 codons (r. .7630_7788del, p.Leu2544_Glu2596del, PP3). Splicing studies performed by two independent laboratories with heterozygous carrier RNA from breast cancer patients confirmed the presence of the predicted transcript with a band intensity comparable to that of the wild-type band (r.7630_7927del p.Leu2544Lysfs*3, O. Díez, unpublished and PMID: 33011440). Sanger sequencing also revealed a very minor transcript corresponding to the out-of-frame skipping of exons 52 and 53 (PMID: 33011440). Although the major transcript is in frame, the skipped exon 52 is located in the FAT domain and contains the nucleotides deleted in the pathogenic in-frame deletion pathogenic variant c.7638_7646del. These RNA results and their expected consequence allow for a funtional supporting code (PS3_Supporting). The c.7788+3A>G variant is absent from the gnomAD v2.1.1 non-cancer dataset, in a position with adequate coverage (>20x) (PM2; http://gnomad.broadinstitute.org). It has been reported in one ataxia-telangiectasia proband in trans with c.5932G > T (p.Glu1978*), which awards it with 1 point as per ClinGen SVI Recommendation for in trans Criterion (PM3, De Stefano, 2016 https://doi.org/10.1515/labmed-2016-0018). Therefore, this variant meets criteria to be classified as pathogenic. Adapted ACMG/AMP rules applied as defined by the Spanish ATM working group: PM2 + PM3 + PP3 + PS3_Supporting (PMID: 33280026). -
not provided Pathogenic:1
Intronic variant demonstrated to result in the in-frame skipping of exon 52, which includes the critical FAT domain, as well as out-of-frame exons 52-53, and exon 53 (Stracker et al., 2014; Rofes et al., 2020); Non-canonical splice site variant expected to result in aberrant splicing; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 33011440, 33280026, 23532176, DeStefano2016[Article]) -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at