2-47790926-G-C
Variant summary
Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong
The NM_000179.3(MSH6):c.261-1G>C variant causes a splice acceptor, intron change. The variant allele was found at a frequency of 0.00000124 in 1,614,090 control chromosomes in the GnomAD database, with no homozygous occurrence. 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_acceptor, 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.261-1G>C | splice_acceptor intron | N/A | NP_000170.1 | |||
| MSH6 | NM_001406830.1 | c.-38G>C | 5_prime_UTR | Exon 2 of 10 | NP_001393759.1 | ||||
| MSH6 | NM_001406795.1 | c.357-1G>C | splice_acceptor intron | N/A | NP_001393724.1 |
Ensembl Transcripts
| Selected | Gene | Transcript | Tags | HGVSc | HGVSp | Effect | Exon Rank | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|---|
| MSH6 | ENST00000234420.11 | TSL:1 MANE Select | c.261-1G>C | splice_acceptor intron | N/A | ENSP00000234420.5 | |||
| MSH6 | ENST00000445503.5 | TSL:1 | n.261-1G>C | splice_acceptor intron | N/A | ENSP00000405294.1 | |||
| MSH6 | ENST00000700002.1 | c.261-1G>C | splice_acceptor intron | N/A | ENSP00000514750.1 |
Frequencies
GnomAD3 genomes AF: 0.00000657 AC: 1AN: 152234Hom.: 0 Cov.: 33 show subpopulations
GnomAD4 exome AF: 6.84e-7 AC: 1AN: 1461856Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1AN XY: 727224 show subpopulations
GnomAD4 genome AF: 0.00000657 AC: 1AN: 152234Hom.: 0 Cov.: 33 AF XY: 0.0000134 AC XY: 1AN XY: 74378 show subpopulations
ClinVar
Submissions by phenotype
not provided Pathogenic:2
Hereditary cancer-predisposing syndrome Pathogenic:2
This variant causes a G to C nucleotide substitution at the -1 position of intron 1 of the MSH6 gene. Splice site prediction tools predict that this variant may have a significant impact on RNA splicing. To our knowledge, RNA studies have not been reported for this variant. This variant has not been reported in individuals affected with Lynch Syndrome in the literature, however has been reported in individuals with Lynch Syndrome in ClinVar (Variation ID: 218055). The variant has also been observed in an individual with pancreatic cancer (PMID: 33747920). This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). Loss of MSH6 function is a known mechanism of disease (clinicalgenome.org). Based on the available evidence, this variant is classified as Likely Pathogenic.
The c.261-1G>C intronic variant results from a G to C substitution one nucleotide upstream from coding exon 2 of the MSH6 gene. This nucleotide position is well conserved in available vertebrate species. This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). In silico splice site analysis predicts that this alteration will weaken the native splice acceptor site and will result in the creation or strengthening of a novel splice acceptor site; however, direct evidence is insufficient at this time (Ambry internal data). 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 likely pathogenic.
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.
Hereditary nonpolyposis colon cancer Pathogenic:1
Variant summary: MSH6 c.261-1G>C is located in a canonical splice-site and is predicted to affect mRNA splicing resulting in a significantly altered protein due to either exon skipping, shortening, or inclusion of intronic material. Several computational tools predict a significant impact on normal splicing: Three predict the variant abolishes a 3' acceptor site. Two predict the variant strengthens a cryptic 3' acceptor site. However, these predictions have yet to be confirmed by functional studies. The variant was absent in 251470 control chromosomes. c.261-1G>C has been reported in the literature in individuals affected with Endometrial Cancer (Long_2019), Breast Cancer (Tung_2015) and Prostate Cancer (Zimmerman_2021). These data indicate that the variant may be associated with Lynch Syndrome. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Two 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 pathogenic (n=1) and likely pathogenic (n=1). Based on the evidence outlined above, the variant was classified as likely pathogenic.
Hereditary nonpolyposis colorectal neoplasms Pathogenic:1
This sequence change affects an acceptor splice site in intron 1 of the MSH6 gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in MSH6 are known to be pathogenic (PMID: 18269114, 24362816). This variant is not present in population databases (gnomAD no frequency). Disruption of this splice site has been observed in individual(s) with Lynch syndrome associated tumors (Invitae). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 218055). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic.
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at