2-47805028-G-T
Variant summary
Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong
The NM_000179.3(MSH6):c.3556+1G>T variant causes a splice donor, intron change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★).
Frequency
Consequence
NM_000179.3 splice_donor, intron
Scores
Clinical Significance
Conservation
Publications
- intellectual developmental disorder with dysmorphic facies and behavioral abnormalitiesInheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, G2P
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ACMG classification
Our verdict: Pathogenic. The variant received 18 ACMG points.
Variant Effect in Transcripts
ACMG analysis was done for transcript: NM_000179.3. You can select a different transcript below to see updated ACMG assignments.
RefSeq Transcripts
| Selected | Gene | Transcript | Tags | HGVSc | HGVSp | Effect | Exon Rank | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|---|
| MSH6 | NM_000179.3 | MANE Select | c.3556+1G>T | splice_donor intron | N/A | NP_000170.1 | |||
| MSH6 | NM_001406795.1 | c.3652+1G>T | splice_donor intron | N/A | NP_001393724.1 | ||||
| MSH6 | NM_001406813.1 | c.3562+1G>T | splice_donor intron | N/A | NP_001393742.1 |
Ensembl Transcripts
| Selected | Gene | Transcript | Tags | HGVSc | HGVSp | Effect | Exon Rank | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|---|
| MSH6 | ENST00000234420.11 | TSL:1 MANE Select | c.3556+1G>T | splice_donor intron | N/A | ENSP00000234420.5 | |||
| MSH6 | ENST00000445503.5 | TSL:1 | n.*2903+1G>T | splice_donor intron | N/A | ENSP00000405294.1 | |||
| MSH6 | ENST00000699999.1 | n.3641G>T | non_coding_transcript_exon | Exon 6 of 9 |
Frequencies
GnomAD3 genomes Cov.: 32
GnomAD4 exome Cov.: 27
GnomAD4 genome Cov.: 32
ClinVar
Submissions by phenotype
Lynch syndrome 5 Pathogenic:1
This variant is considered likely pathogenic. This variant occurs within a consensus splice junction and is predicted to result in abnormal mRNA splicing of either an out-of-frame exon or an in-frame exon necessary for protein stability and/or normal function.
Lynch syndrome Pathogenic:1
The c.3556+1G>T variant in MSH6 has been reported in 1 individual with MSH6-asso ciated cancers (Hirotsu 2015) and was absent from large population studies. The c.3556+1G>T variant occurs in the invariant region (+/- 1,2) of the splice conse nsus sequence and is predicted to cause altered splicing leading to an abnormal or absent protein. In vitro functional studies provide some evidence that this v ariant causes nonsense mediated decay of MSH6 mRNA and microsatellite instabilit y in tumor sample (Hirotsu 2015). Heterozygous loss of function of the MSH6 gene is an established disease mechanism in Lynch syndrome. In addition, this varian t was classified as pathogenic on Aug 10, 2016 by the ClinGen-approved InSiGHT e xpert panel (ClinVar SCV000551216.1). In summary, this variant meets criteria to be classified as pathogenic for Lynch syndrome in an autosomal dominant manner. ACMG/AMP Criteria applied: PVS1; PM2; PS3_Moderate, PS4_Supporting.
MSH6-related disorder Pathogenic:1
The MSH6 c.3556+1G>T variant is predicted to disrupt the GT donor site and interfere with normal splicing. This variant has been reported in an individual with Lynch syndrome (reported as IVS6+1G>T in Hirotsu et al 2015. PubMed ID: 26436112). In the paper of Hirotsu et al 2015, mRNA expression level of MSH6 was significantly reduced in patient's compared with controls while (microsatellite instability) MSI analysis and immunohistochemistry staining showed tumors had high MSI and lacked MSH6 protein expression. This variant has not been reported in a large population database, indicating this variant is rare. This variant is interpreted as pathogenic or likely pathogenic in ClinVar (https://www.ncbi.nlm.nih.gov/clinvar/variation/646634/). Variants that disrupt the consensus splice donor site in MSH6 are expected to be pathogenic. This variant is interpreted as pathogenic.
Gastric cancer Pathogenic:1
not provided Pathogenic:1
Canonical splice site variant demonstrated to result in a null allele in a gene for which loss of function is a known mechanism of disease (PMID: 26436112); Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 26436112, 32980694, 33309985)
Hereditary nonpolyposis colorectal neoplasms Pathogenic:1
This sequence change affects a donor splice site in intron 6 of the MSH6 gene. RNA analysis indicates that disruption of this splice site induces altered splicing and may result in an absent or altered protein product. This variant is not present in population databases (gnomAD no frequency). Disruption of this splice site has been observed in individuals with Lynch syndrome (PMID: 26436112; internal data). ClinVar contains an entry for this variant (Variation ID: 646634). Studies have shown that disruption of this splice site results in skipping of exon 6, and produces a non-functional protein and/or introduces a premature termination codon (PMID: 26436112; internal data). For these reasons, this variant has been classified as Pathogenic.
Hereditary cancer-predisposing syndrome Pathogenic:1
The c.3556+1G>T intronic pathogenic mutation results from a G to T substitution one nucleotide after coding exon 6 of the MSH6 gene. This variant has been identified in a proband(s) whose Lynch syndrome-associated tumor demonstrated loss of MSH6 expression by immunohistochemistry (Li S et al. J. Med. Genet. 2020 Jan;57:62-69; Ambry internal data). Other variant(s) impacting the same donor site (c.3556+1G>A) have been identified in individual(s) with features consistent with MSH6-related Lynch syndrome (Ambry internal data). This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). 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. Alterations that disrupt the canonical splice site are expected to cause aberrant splicing, resulting in an abnormal protein or a transcript that is subject to nonsense-mediated mRNA decay. As such, this alteration is classified as a disease-causing mutation.
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at