2-47799333-AT-A

Position:

• chr2-47799333-AT-A

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.1352del​(p.Phe451SerfsTer2) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000342 in 1,461,736 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. F451F) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000034 (0 hom.)
• Consequence: MSH6 NM_000179.3 frameshift
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:11
• Conservation: PhyloP100: 7.99

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 2-47799333-AT-A is Pathogenic according to our data. Variant chr2-47799333-AT-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 224534.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MSH6	NM_000179.3	c.1352del	p.Phe451SerfsTer2	frameshift_variant	4/10	ENST00000234420.11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MSH6	ENST00000234420.11	c.1352del	p.Phe451SerfsTer2	frameshift_variant	4/10	1	NM_000179.3	P4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000342 AC: 5 AN: 1461736 Hom.: 0 Cov.: 34 AF XY: 0.00000138 AC XY: 1 AN XY: 727170

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: 0.00000450

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:11

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Lynch syndrome Pathogenic:3

Likely pathogenic, criteria provided, single submitter	clinical testing	Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine	Oct 14, 2019	The p.Phe451SerfsX2 variant in MSH6 has been reported in at least 1 individual with colorectal cancer (Shirts 2016) and was absent from large population studies. It has also been reported in ClinVar (Variation ID 224534) and classified as Pathogenic by several clinical labs. This variant is predicted to cause a frameshift, which alters the protein’s amino acid sequence beginning at position 451 and leads to a premature termination codon 2 amino acids downstream. This alteration is then predicted to lead to a truncated or absent protein. Loss of function of the MSH6 gene is an established disease mechanism in autosomal dominant Lynch syndrome. In summary, although additional studies are required to fully establish its clinical significance, the p.Phe451SerfsX2 variant meets criteria to be classified as likely pathogenic for Lynch syndrome. ACMG/AMP criteria applied: PVS1, PM2 -
Likely pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Feb 07, 2020	Variant summary: MSH6 c.1352delT (p.Phe451SerfsX2) 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 251008 control chromosomes (gnomAD). c.1352delT has been reported in the literature in at least one individual affected with small intestine cancer and polyposis (Shirts_2015). These report(s) do not provide unequivocal conclusions about association of the variant with Hereditary Non-Polyposis Colon Cancer. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. 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 (4x) / likely pathogenic (1x). Based on the evidence outlined above, the variant was classified as likely pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	University of Washington Department of Laboratory Medicine, University of Washington	Nov 20, 2015	- -

not provided Pathogenic:3

Likely pathogenic, no assertion criteria provided	clinical testing	Mayo Clinic Laboratories, Mayo Clinic	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	Quest Diagnostics Nichols Institute San Juan Capistrano	May 14, 2022	This frameshift variant alters the translational reading frame of the MSH6 mRNA and causes the premature termination of MSH6 protein synthesis. It has not been reported in large, multi-ethnic general populations (http://gnomad.broadinstitute.org). In the published literature, this variant has been reported in an individual with cancer of the small intestine and in a healthy control individual (PMIDs: 26845104 (2016) and 33471991 (2021); https://databases.lovd.nl/shared/). Based on the available information, this variant is classified as pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Jul 31, 2018	This deletion of one nucleotide in MSH6 is denoted c.1352delT at the cDNA level and p.Phe451SerfsX2 (F451SfsX2) at the protein level. The normal sequence, with the base that is deleted in braces, is GTAT[T]CATG. The deletion causes a frameshift which changes a Phenylalanine to a Serine at codon 451, and creates a premature stop codon at position 2 of the new reading frame. Although this variant has not, to our knowledge, been reported in the literature, it is predicted to cause loss of normal protein function through either protein truncation or nonsense-mediated mRNA decay. We consider this variant to be pathogenic. -

Hereditary cancer-predisposing syndrome Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Jan 15, 2020	This variant deletes 1 nucleotide in exon 4 of the MSH6 gene, creating a frameshift and premature translation stop signal. This variant is expected to result in an absent or non-functional protein product. 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	Nov 22, 2021	The c.1352delT pathogenic mutation, located in coding exon 4 of the MSH6 gene, results from a deletion of one nucleotide at nucleotide position 1352, causing a translational frameshift with a predicted alternate stop codon (p.F451Sfs*2). This alteration was detected in a cohort of 29,906 healthy individuals who underwent multigene panel testing (Grzymski JJ et al. Nat Med, 2020 08;26:1235-1239). This variant has also been identified in individuals with Lynch syndrome, including a patient with MSI-H cancer of the small intestine (Shirts BH et al. Genet Med, 2016 10;18:974-81; Patel AP et al. JAMA Netw Open, 2020 04;3:e203959). 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. -

Lynch syndrome 5 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Myriad Genetics, Inc.

Aug 14, 2023

This variant is considered pathogenic. This variant creates a frameshift predicted to result in premature protein truncation. -

Hereditary nonpolyposis colorectal neoplasms Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Sep 27, 2023

This sequence change creates a premature translational stop signal (p.Phe451Serfs*2) 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 not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individual(s) with small intestine cancer and polyposis (PMID: 26845104). ClinVar contains an entry for this variant (Variation ID: 224534). For these reasons, this variant has been classified as Pathogenic. -

Endometrial carcinoma Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Baylor Genetics

Jan 04, 2023

- -

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: rs869312769; hg19: chr2-48026472;