2-47798725-C-T

Position:

• chr2-47798725-C-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.742C>T​(p.Arg248Ter) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,870 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★★). Synonymous variant affecting the same amino acid position (i.e. R248R) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: MSH6 NM_000179.3 stop_gained
• Clinical Significance: Pathogenic reviewed by expert panel P:15
• Conservation: PhyloP100: 0.846

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: 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 2-47798725-C-T is Pathogenic according to our data. Variant chr2-47798725-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 89563.Status of the report is reviewed_by_expert_panel, 3 stars. Variant chr2-47798725-C-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MSH6	NM_000179.3	c.742C>T	p.Arg248Ter	stop_gained	4/10	ENST00000234420.11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MSH6	ENST00000234420.11	c.742C>T	p.Arg248Ter	stop_gained	4/10	1	NM_000179.3	P4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461870 Hom.: 0 Cov.: 34 AF XY: 0.00000138 AC XY: 1 AN XY: 727236

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: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:15

Revision: reviewed by expert panel

Submissions by phenotype

not provided Pathogenic:4

Pathogenic, criteria provided, single submitter	clinical testing	Mayo Clinic Laboratories, Mayo Clinic	Mar 30, 2023	PP4, PP5, PM2, PVS1 -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Jan 28, 2022	Nonsense 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; Observed in individuals with a personal and/or family history of MSH6-related cancers (Wijnen 1999, Steinke 2008, Tsukanov 2021); Not observed at significant frequency in large population cohorts (gnomAD); Truncating variants in this gene are considered pathogenic by a well-established clinical consortium and/or database; This variant is associated with the following publications: (PMID: 25525159, 33087929, 33937060, 30787465, 10508506, 15236168, 12547705, 20028993, 18301448, 29625052, 28502729) -
Pathogenic, criteria provided, single submitter	clinical testing	Quest Diagnostics Nichols Institute San Juan Capistrano	Mar 25, 2019	The variant creates a premature nonsense codon, and is therefore predicted to result in the loss of a functional protein. Found in at least one symptomatic patient, and not found in general population data. -
Pathogenic, criteria provided, single submitter	clinical testing	Center for Genomic Medicine, Rigshospitalet, Copenhagen University Hospital	Aug 15, 2023	- -

Lynch syndrome Pathogenic:3

Pathogenic, criteria provided, single submitter	clinical testing	All of Us Research Program, National Institutes of Health	Apr 10, 2023	This variant changes 1 nucleotide in exon 4 of the MSH6 gene, creating a premature translation stop signal. This variant is expected to result in an absent or non-functional protein product. This variant has been reported in individuals and families affected with Lynch syndrome, with tumor analyses showing microsatellite instability and/or loss of MSH6 protein by immunohistochemistry analyses (PMID: 10508506, 12547705, 18301448, 33937060). 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 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 -
Pathogenic, criteria provided, single submitter	clinical testing	Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine	Oct 14, 2019	The p.Arg248X variant in MSH6 has been previously reported in 1 individual with Lynch syndrome (Steinke 2008) and 2 individuals with colorectal cancer (Wijnen 1999, Hendricks 2003). It was absent from large population studies. This variant was classified as Pathogenic on September 5, 2013 by the ClinGen-approved InSiGHT expert panel (Variation ID 89563). This nonsense variant leads to a premature termination codon at position 248, which is predicted to lead to a truncated or absent protein. Heterozygous loss of function of the MSH6 gene is an established disease mechanism in individuals with Lynch syndrome. In summary, this variant meets criteria to be classified as pathogenic for autosomal dominant Lynch syndrome. ACMG/AMP criteria applied: PVS1, PM2, PS4_Supporting. -

Hereditary cancer-predisposing syndrome Pathogenic:3

Pathogenic, criteria provided, single submitter	curation	Sema4, Sema4	Apr 13, 2021	- -
Pathogenic, criteria provided, single submitter	clinical testing	Ambry Genetics	Jul 30, 2021	The p.R248* pathogenic mutation (also known as c.742C>T), located in coding exon 4 of the MSH6 gene, results from a C to T substitution at nucleotide position 742. This changes the amino acid from an arginine to a stop codon within coding exon 4. This alteration has been reported in multiple individuals with Lynch syndrome-associated cancers (Wijnen J et al. Nat. Genet. 1999 Oct;23(2):142-4; Steinke V et al. Eur. J. Hum. Genet. 2008 May;16(5):587-92; Chao X et al. Cancer Commun (Lond), 2019 07;39:42; Tsukanov AS et al. Front Oncol, 2021 Apr;11:652696). In one study, authors reported this pathogenic mutation in an individual diagnosed with colon cancer at age 26 whose tumor showed high microsatellite instability and absent MSH6 staining on IHC (Hendriks Y et al. Am. J. Pathol. 2003 Feb;162(2):469-77). Additionally, this variant was reported in 1/60,466 breast cancer cases and in 0/53,461 controls (Dorling et al. N Engl J Med. 2021 02;384:428-439). This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). 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. -
Pathogenic, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Feb 01, 2023	This variant changes 1 nucleotide in exon 4 of the MSH6 gene, creating a premature translation stop signal. This variant is expected to result in an absent or non-functional protein product. This variant has been reported in individuals and families affected with Lynch syndrome, with tumor analyses showing microsatellite instability and/or loss of MSH6 protein by immunohistochemistry analyses (PMID: 10508506, 12547705, 18301448, 33937060). 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 Pathogenic. -

Lynch syndrome 5 Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	MGZ Medical Genetics Center	Feb 09, 2022	- -
Pathogenic, criteria provided, single submitter	clinical testing	Myriad Genetics, Inc.	Aug 10, 2023	This variant is considered pathogenic. This variant creates a termination codon and is predicted to result in premature protein truncation. -

Hereditary nonpolyposis colon cancer Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Dec 04, 2023

Variant summary: MSH6 c.742C>T (p.Arg248X) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. Truncations downstream of this position have been classified as pathogenic by our laboratory (eg. c.892C>T, p.Arg298X; c.1135_1139delAGAGA, p.Arg379X; c.1190_1191delAT, p.Tyr397fsX3). The variant was absent in 276846 control chromosomes (gnomAD). c.742C>T has been reported in the literature in individuals affected with Lynch Syndrome; analysis of tumor samples showed loss of MSH6 protein expression via immunohistochemistry and high microsatellite instability (Tsukanov_2021, Steinke_2008, Hendriks_2003, Wijnen_1999). These data indicate that the variant is likely associated with disease. The following publications have been ascertained in the context of this evaluation (PMID: 12547705, 15236168, 28152038, 18301448, 33937060, 10508506). Seven submitters have cited clinical-significance assessments for this variant to ClinVar after 2014; all submitters classified the variant as pathogenic/likely pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -

Hereditary nonpolyposis colorectal neoplasms Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Sep 11, 2023

For these reasons, this variant has been classified as Pathogenic. ClinVar contains an entry for this variant (Variation ID: 89563). This premature translational stop signal has been observed in individual(s) with Lynch syndrome (PMID: 10508506, 18301448). This variant is not present in population databases (gnomAD no frequency). This sequence change creates a premature translational stop signal (p.Arg248*) 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). -

Endometrial carcinoma Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Baylor Genetics

Nov 22, 2022

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.50	D
BayesDel_noAF	Pathogenic	0.48
CADD	Pathogenic	36
DANN	Uncertain	1.0
Eigen	Uncertain	0.49
Eigen_PC	Uncertain	0.31
FATHMM_MKL	Uncertain	0.83	D
MutationTaster	Benign	1.0	D;A;A;D
Vest4		0.89
GERP RS		3.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1

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: rs63749980; hg19: chr2-48025864; COSMIC: COSV99316661; COSMIC: COSV99316661;