rs63750439

Positions:

• chr2-47799171-CTA-C
• chr2-47799171-CTA-CTATA

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.1190_1191delAT​(p.Tyr397fs) variant causes a frameshift change. The variant allele was found at a frequency of 0.00000137 in 1,461,868 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: MSH6 NM_000179.3 frameshift
• Clinical Significance: Pathogenic reviewed by expert panel P:12 O:1
• Conservation: PhyloP100: 4.08

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]

MSH6 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 2-47799171-CTA-C is Pathogenic according to our data. Variant chr2-47799171-CTA-C is described in ClinVar as [Pathogenic]. Clinvar id is 89178.Status of the report is reviewed_by_expert_panel, 3 stars. Variant chr2-47799171-CTA-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MSH6	NM_000179.3	c.1190_1191delAT	p.Tyr397fs	frameshift_variant	4/10	ENST00000234420.11	NP_000170.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MSH6	ENST00000234420.11	c.1190_1191delAT	p.Tyr397fs	frameshift_variant	4/10	1	NM_000179.3	ENSP00000234420.5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000796 AC: 2 AN: 251136 Hom.: 0 AF XY: 0.00000737 AC XY: 1 AN XY: 135752

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000289

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000881

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461868 Hom.: 0 AF XY: 0.00000138 AC XY: 1 AN XY: 727238

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000224

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: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:12 Other:1

Revision: reviewed by expert panel

Submissions by phenotype

not provided Pathogenic:3

Pathogenic, criteria provided, single submitter	clinical testing	Clinical Genetics and Genomics, Karolinska University Hospital	Feb 14, 2017	- -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Jun 09, 2023	Frameshift variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss-of-function is a known mechanism of disease; Truncating variants in this gene are considered pathogenic by a well-established clinical consortium and/or database; Not observed at significant frequency in large population cohorts (gnomAD); Observed in individuals with early-onset colon cancer who had tumors showing microsatellite instability and/or loss of MSH6 on immunohistochemistry staining (Plaschke et al., 2004; Steinke et al., 2008; You et al., 2010; Yang et al., 2021); This variant is associated with the following publications: (PMID: 14974087, 32980694, 29922827, 18301448, 21081928, 26681312, 15483016, 36988593, 34178123) -
Pathogenic, no assertion criteria provided	clinical testing	Mayo Clinic Laboratories, Mayo Clinic	-	- -

Lynch syndrome 5 Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Myriad Genetics, Inc.	Aug 11, 2023	This variant is considered pathogenic. This variant creates a frameshift predicted to result in premature protein truncation. -
Pathogenic, criteria provided, single submitter	clinical testing	New York Genome Center	Jun 23, 2021	The inherited c.1190_1191del (p.Tyr397CysfsTer3) variant identified in the MSH6 gene is the deletion of two nucleotides resulting in a frameshift of the protein at amino acid 397/1361 (exon 4/10), which is predicted to lead to the termination of the protein approximately 3 amino acids downstream. This variant is absent from gnomAD(v3.1.1) suggesting it is not a common benign variant in the populations represented in that database. This variant has been reviewedby an Expert Panel and reported in ClinVar as Pathogenic (VarID:89178) and has been reported in several affected individuals in the literature [PMID:15483016,18301448, 21081928]. The inherited c.1190_1191del (p.Tyr397CysfsTer3) variant identified in the MSH6 gene is reported as Pathogenic. -

Lynch syndrome Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Nov 15, 2017	Variant summary: The MSH6 c.1190_1191delAT (p.Tyr397CysfsX3) variant results in a premature termination codon, predicted to cause a truncated or absent MSH6 protein due to nonsense mediated decay, which are commonly known mechanisms for disease. One in silico tool predicts a damaging outcome for this variant. Truncations downstream of this position have been classified as pathogenic by our laboratory (e.g. c.1444C>T (p.Arg482X), c.1572C>A (p.Tyr524X), c.1634_1637delAAGA (p.Lys545fsX25)). The variant has been observed in patients with HNPCC-associated cancers (i.e. CRC and cancer of the endometrium), in one of them a CRC tumor sample showing loss of MSH6 and microsatellite instability (Plaschke 2004, Susswein 2015). This variant was found in 2/245974 control chromosomes at a frequency of 0.0000081, which does not exceed the estimated maximal expected allele frequency of a pathogenic MSH6 variant (0.0001421). In addition, multiple clinical diagnostic laboratories/reputable databases classified this variant as pathogenic. Taken together, this variant is classified as pathogenic. -
Pathogenic, reviewed by expert panel	research	International Society for Gastrointestinal Hereditary Tumours (InSiGHT)	Sep 05, 2013	Coding sequence variation resulting in a stop codon -

Hereditary cancer-predisposing syndrome Pathogenic:2

Pathogenic, criteria provided, single submitter	curation	Sema4, Sema4	May 08, 2021	- -
Pathogenic, criteria provided, single submitter	clinical testing	Ambry Genetics	Jun 06, 2022	The c.1190_1191delAT pathogenic mutation, located in coding exon 4 of the MSH6 gene, results from a deletion of two nucleotides at nucleotide positions 1190 to 1191, causing a translational frameshift with a predicted alternate stop codon (p.Y397Cfs*3). This mutation was previously reported in an individual with a sigmoid colon tumor at age 33 that was noted to be MSI-H and have absent MSH6 expression by IHC analysis (Plaschke J et al. Hum. Mutat. 2004 Mar;23:285). In addition to the clinical data presented in the literature, this alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. As such, this alteration is interpreted as a disease-causing mutation. -

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

Jan 24, 2024

This sequence change creates a premature translational stop signal (p.Tyr397Cysfs*3) in the MSH6 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in MSH6 are known to be pathogenic (PMID: 18269114, 24362816). This variant is present in population databases (rs756896277, gnomAD 0.003%). This premature translational stop signal has been observed in individual(s) with Lynch syndrome (PMID: 14974087, 15483016, 26681312). ClinVar contains an entry for this variant (Variation ID: 89178). For these reasons, this variant has been classified as Pathogenic. -

Endometrial carcinoma Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Baylor Genetics

Mar 20, 2024

- -

Hereditary nonpolyposis colon cancer;C4552100:Lynch syndrome Other:1

not provided, no classification provided

phenotyping only

GenomeConnect - Invitae Patient Insights Network

-

Variant interpreted as Pathogenic and reported on 07-12-2017 by Myriad. GenomeConnect-Invitae Patient Insights Network assertions are reported exactly as they appear on the patient-provided report from the testing laboratory. Registry team members make no attempt to reinterpret the clinical significance of the variant. Phenotypic details are available under supporting information. -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

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

Publications

LitVar

Other links and lift over

dbSNP: rs63750439; hg19: chr2-48026310;