2-47805028-G-T

Position:

• chr2-47805028-G-T

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000179.3(MSH6):​c.3556+1G>T variant causes a splice donor 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: Genomes: not found (cov: 32)
• Consequence: MSH6 NM_000179.3 splice_donor
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:6
• Conservation: PhyloP100: 9.34

Genes affected

MSH6 (HGNC:7329): (mutS homolog 6) This gene encodes a member of the DNA mismatch repair MutS family. In E. coli, the MutS protein helps in the recognition of mismatched nucleotides prior to their repair. A highly conserved region of approximately 150 aa, called the Walker-A adenine nucleotide binding motif, exists in MutS homologs. The encoded protein heterodimerizes with MSH2 to form a mismatch recognition complex that functions as a bidirectional molecular switch that exchanges ADP and ATP as DNA mismatches are bound and dissociated. Mutations in this gene may be associated with hereditary nonpolyposis colon cancer, colorectal cancer, and endometrial cancer. Transcripts variants encoding different isoforms have been described. [provided by RefSeq, Jul 2013]

FBXO11 (HGNC:13590): (F-box protein 11) This gene encodes a member of the F-box protein family which is characterized by an approximately 40 amino acid motif, the F-box. The F-box proteins constitute one of the four subunits of ubiquitin protein ligase complex called SCFs (SKP1-cullin-F-box), which function in phosphorylation-dependent ubiquitination. The F-box proteins are divided into 3 classes: Fbws containing WD-40 domains, Fbls containing leucine-rich repeats, and Fbxs containing either different protein-protein interaction modules or no recognizable motifs. The protein encoded by this gene belongs to the Fbxs class. It can function as an arginine methyltransferase that symmetrically dimethylates arginine residues, and it acts as an adaptor protein to mediate the neddylation of p53, which leads to the suppression of p53 function. This gene is known to be down-regulated in melanocytes from patients with vitiligo, a skin disorder that results in depigmentation. Polymorphisms in this gene are associated with chronic otitis media with effusion and recurrent otitis media (COME/ROM), a hearing loss disorder, and the knockout of the homologous mouse gene results in the deaf mouse mutant Jeff (Jf), a single gene model of otitis media. Alternatively spliced transcript variants encoding distinct isoforms have been identified for this gene. [provided by RefSeq, Jun 2010]

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, No cryptic splice site detected. Exon removal results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 2-47805028-G-T is Pathogenic according to our data. Variant chr2-47805028-G-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 646634.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MSH6	NM_000179.3	c.3556+1G>T		splice_donor_variant		ENST00000234420.11	NP_000170.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MSH6	ENST00000234420.11	c.3556+1G>T		splice_donor_variant		1	NM_000179.3	ENSP00000234420	P4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 27

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:6

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Lynch syndrome 5 Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Myriad Genetics, Inc.

Aug 24, 2023

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. -

MSH6-related disorder Pathogenic:1

Pathogenic, no assertion criteria provided

clinical testing

PreventionGenetics, part of Exact Sciences

Jun 29, 2024

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. -

Lynch syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Dec 05, 2017

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. -

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

May 28, 2024

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) -

Gastric cancer Pathogenic:1

Pathogenic, no assertion criteria provided

research

Laboratory for Genotyping Development, RIKEN

Jul 01, 2021

- -

Hereditary nonpolyposis colorectal neoplasms Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 17, 2023

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 disrupted 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; Invitae). 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 introduces a premature termination codon (PMID: 26436112; Invitae). The resulting mRNA is expected to undergo nonsense-mediated decay. For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.40	D
BayesDel_noAF	Pathogenic	0.34
CADD	Pathogenic	34
DANN	Uncertain	1.0
Eigen	Pathogenic	1.2
Eigen_PC	Pathogenic	0.99
FATHMM_MKL	Pathogenic	0.99	D
MutationTaster	Benign	1.0	D;D;D;D
GERP RS		4.7

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.94
SpliceAI score (max)		1.0		Details are displayed if max score is > 0.2
DS_DL_spliceai		1.0		Position offset: -1

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs1060502926; hg19: chr2-48032167;