rs267608068

Positions:

• chr2-47800044-T-A
• chr2-47800044-T-C
• chr2-47800044-T-G

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.2061T>A​(p.Cys687Ter) 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 1,461,858 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 (★★★). 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:10
• Conservation: PhyloP100: 2.44

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 2-47800044-T-A is Pathogenic according to our data. Variant chr2-47800044-T-A is described in ClinVar as [Pathogenic]. Clinvar id is 89246.Status of the report is reviewed_by_expert_panel, 3 stars. Variant chr2-47800044-T-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MSH6	NM_000179.3	c.2061T>A	p.Cys687Ter	stop_gained	4/10	ENST00000234420.11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MSH6	ENST00000234420.11	c.2061T>A	p.Cys687Ter	stop_gained	4/10	1	NM_000179.3	P4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461858 Hom.: 0 Cov.: 34 AF XY: 0.00 AC XY: 0 AN XY: 727230

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: 8.99e-7

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:10

Revision: reviewed by expert panel

Submissions by phenotype

not provided Pathogenic:3

Likely pathogenic, no assertion criteria provided	clinical testing	Mayo Clinic Laboratories, Mayo Clinic	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Oct 26, 2017	This pathogenic variant is denoted MSH6 c.2061T>A at the cDNA level and p.Cys687Ter (C687X) atthe protein level. The substitution creates a nonsense variant, which changes a Cysteine to a premature stop codon(TGT>TGA), and is predicted to cause loss of normal protein function through either protein truncation or nonsense-mediated mRNA decay. This variant has been reported in an individual with a tubular adenoma and in a Scottish familywith multiple cases of colorectal or Lynch syndrome cancers (Pino 2009, Baglietto 2010), and is consideredpathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Quest Diagnostics Nichols Institute San Juan Capistrano	May 18, 2021	This nonsense variant causes the premature termination of MSH6 protein synthesis. In addition, it has been reported in an individual with Lynch syndrome in the published literature (PMID: 19324997 (2009)). Based on the available information, this variant is classified as pathogenic. -

Hereditary cancer-predisposing syndrome Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Jul 26, 2021	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. To our knowledge, functional studies have not been reported for this variant. This variant has been reported in individuals affected with Lynch syndrome (PMID: (19324997, 34039291). 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, criteria provided, single submitter	clinical testing	Ambry Genetics	May 12, 2023	The p.C687* pathogenic mutation (also known as c.2061T>A), located in coding exon 4 of the MSH6 gene, results from a T to A substitution at nucleotide position 2061. This changes the amino acid from a cystine to a stop codon within coding exon 4. In one study, this mutation was reported in an individual from Scotland who was diagnosed with colorectal cancer prior to 55 years of age (Baglietto L et al. J Natl Cancer Inst. 2010 Feb 3;102(3):193-201). 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. -

Lynch syndrome 5 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Myriad Genetics, Inc.

Aug 16, 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

Mar 19, 2022

Variant summary: MSH6 c.2061T>A (p.Cys687X) 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. The variant was absent in 250560 control chromosomes. c.2061T>A has been reported in the literature in at-least two reports of individuals affected with Lynch Syndrome (example, Pino_2009, Baglietto_2010). Five 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. Based on the evidence outlined above, the variant was classified as pathogenic. -

Lynch syndrome Pathogenic:1

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 nonpolyposis colorectal neoplasms Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Jun 27, 2023

This premature translational stop signal has been observed in individual(s) with Lynch syndrome (PMID: 19324997). For these reasons, this variant has been classified as Pathogenic. ClinVar contains an entry for this variant (Variation ID: 89246). This variant is not present in population databases (gnomAD no frequency). This sequence change creates a premature translational stop signal (p.Cys687*) 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, no assertion criteria provided

clinical testing

Department of Pathology and Laboratory Medicine, Sinai Health System

-

The p.Cys687X variant was not identified in the literature nor was it identified in the NHLBI Exome Sequencing Project (Exome Variant Server), Exome Aggregation Consortium (ExAC), COSMIC, Mismatch Repair Genes Variant, “MMR Gene Unclassified Variants, Zhejiang Colon Cancer, GeneInsight through the Canadian Open Genetics Repository (http://opengenetics.ca/) databases. The variant was identified in dbSNP (ID: rs 267608068 “With Pathogenic allele”, in InSiGHT Colon Cancer Database (2x classified as pathogenic), in Clinvitae (2x classified as pathogenic), in LOVD as unknown. In the ClinVar database, the variant is classified as a pathogenic variant by InSIGHT and Ambry Genetics. The p.Cys687X variant leads to a premature stop codon at position 687, which is predicted to lead to a truncated or absent protein and loss of function. Loss of function variants of the MSH6 gene are an established mechanism of disease in Lynch syndrome and this is the type of variant expected to cause the disorder. In summary, based on the above information, this variant meets our laboratory’s criteria to be classified as pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.53	D
BayesDel_noAF	Pathogenic	0.53
CADD	Pathogenic	36
DANN	Uncertain	0.99
Eigen	Uncertain	0.58
Eigen_PC	Uncertain	0.43
FATHMM_MKL	Uncertain	0.95	D
MutationTaster	Benign	1.0	D;A;A;A
Vest4		0.89
GERP RS		3.9
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.8

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: rs267608068; hg19: chr2-48027183;