2-47806653-T-C

Position:

• chr2-47806653-T-C

Variant summary

Our verdict is Pathogenic. Variant got 19 ACMG points: 19P and 0B. PVS1 PM2 PP3 PP5_Very_Strong

The NM_000179.3(MSH6):​c.4001+2T>C variant causes a splice donor change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000069 in 1,449,400 control chromosomes in the GnomAD database, with no homozygous occurrence. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: MSH6 NM_000179.3 splice_donor
• Scores: Splicing: ADA: 0.9768
• Clinical Significance: Pathogenic reviewed by expert panel P:5
• Conservation: PhyloP100: 0.0550

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 19 ACMG points.

• PVS1: Splicing 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
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, max_spliceai. No scorers claiming Uncertain. Scorers claiming Benign: dbscSNV1_RF.
• PP5: Variant 2-47806653-T-C is Pathogenic according to our data. Variant chr2-47806653-T-C is described in ClinVar as [Pathogenic]. Clinvar id is 89501.Status of the report is reviewed_by_expert_panel, 3 stars. Variant chr2-47806653-T-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MSH6	NM_000179.3	c.4001+2T>C		splice_donor_variant		ENST00000234420.11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MSH6	ENST00000234420.11	c.4001+2T>C		splice_donor_variant		1	NM_000179.3	P4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.90e-7 AC: 1 AN: 1449400 Hom.: 0 Cov.: 34 AF XY: 0.00000139 AC XY: 1 AN XY: 721442

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 9.05e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:5

Revision: reviewed by expert panel

Submissions by phenotype

Lynch syndrome 5 Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Myriad Genetics, Inc.

Aug 29, 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. -

Lynch syndrome Pathogenic:1

Pathogenic, reviewed by expert panel

research

International Society for Gastrointestinal Hereditary Tumours (InSiGHT)

Sep 05, 2013

Variant causes splicing aberration, >2 MSI-H, co-segregation with disease & absent in 1000 genomes -

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Center for Genomic Medicine, Rigshospitalet, Copenhagen University Hospital

Jul 31, 2024

- -

Hereditary nonpolyposis colorectal neoplasms Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Invitae

Oct 26, 2018

In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. Nucleotide substitutions within the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site, but this prediction has not been confirmed by published transcriptional studies. This variant has been observed to segregate with disease in a Lynch syndrome family and has been observed in several individuals and families with suspected Lynch syndrome (PMID: 18566915, 21836479, 25648859, 22495361). ClinVar contains an entry for this variant (Variation ID: 89501). This variant is not present in population databases (ExAC no frequency). This sequence change affects a donor splice site in the last intron (intron 9) of the MSH6 gene. While this is not anticipated to result in nonsense mediated decay, it likely alters RNA splicing and results in a disrupted protein product. -

Hereditary cancer-predisposing syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Sep 15, 2022

The c.4001+2T>C intronic pathogenic mutation results from a T to C substitution two nucleotides after coding exon 9 in the MSH6 gene. This alteration occurs at the 3' terminus of the MSH6 gene and is not expected to trigger nonsense-mediated mRNA decay. The exact functional effect of this alteration is unknown; however, the impacted region is critical for protein function (Ambry internal data). This mutation has been reported in several Danish HNPCC/Lynch syndrome families (Nilbert M et al. Fam. Cancer 2009;8(1):75-83; Jensen UB et al. Breast Cancer Res. Treat., 2010 Apr;120:777-82; Okkels H et al. Appl Immunohistochem Mol Morphol. 2012 Oct;20(5):470-7; Therkildsen C et al. Eur. J. Neurol., 2015 Apr;22:717-24). This variant has also been identified in probands whose HNPCC/Lynch syndrome-associated tumors demonstrated loss of MSH6 expression by immunohistochemistry (Ambry internal data). RNA studies have demonstrated that this alteration results in abnormal splicing in the set of samples tested (Ambry internal data). Based on the supporting evidence, this alteration is interpreted as a disease-causing mutation. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Uncertain	0.12	D
BayesDel_noAF	Uncertain	-0.070
CADD	Benign	22
DANN	Uncertain	0.98
Eigen	Pathogenic	0.87
Eigen_PC	Pathogenic	0.71
FATHMM_MKL	Uncertain	0.97	D
MutationTaster	Benign	1.0	D;D;D;D
GERP RS		4.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	0.98
dbscSNV1_RF	Benign	0.66
SpliceAI score (max)		0.98		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.98		Position offset: -2

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

Publications

LitVar

Other links and lift over

dbSNP: rs267608131; hg19: chr2-48033792;