NM_000179.3:c.2779dupA

Variant names:

• chr2-47800761-T-TA
• rs587782277
• NM_000179.3:c.2779dupA

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.2779dupA​(p.Ile927AsnfsTer8) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,856 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: MSH6 NM_000179.3 frameshift
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:11
• Conservation: PhyloP100: 9.29

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 2-47800761-T-TA is Pathogenic according to our data. Variant chr2-47800761-T-TA is described in ClinVar as [Likely_pathogenic]. Clinvar id is 142168.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MSH6	NM_000179.3	c.2779dupA	p.Ile927AsnfsTer8	frameshift_variant	Exon 4 of 10	ENST00000234420.11	NP_000170.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MSH6	ENST00000234420.11	c.2779dupA	p.Ile927AsnfsTer8	frameshift_variant	Exon 4 of 10	1	NM_000179.3	ENSP00000234420.5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000797 AC: 2 AN: 250978 Hom.: 0 AF XY: 0.00000737 AC XY: 1 AN XY: 135692

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

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: 0.0000176

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461856 Hom.: 0 Cov.: 34 AF XY: 0.00000138 AC XY: 1 AN XY: 727226

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: 0.00000270

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

not provided Pathogenic:4

Jun 17, 2022

Clinical Genetics Laboratory, Skane University Hospital Lund

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jun 01, 2023

CeGaT Center for Human Genetics Tuebingen

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

MSH6: PVS1, PM2 -

Jan 10, 2017

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This duplication of one nucleotide in MSH6 is denoted c.2779dupA at the cDNA level and p.Ile927AsnfsX8 (I927NfsX8) at the protein level. The normal sequence, with the base that is duplicated in brackets, is ACTT[A]TTAC. The duplication causes a frameshift, which changes an Isoleucine to an Asparagine at codon 927, and creates a premature stop codon at position 8 of the new reading frame. This variant is predicted to cause loss of normal protein function through either protein truncation or nonsense-mediated mRNA decay. MSH6 c.2779dupA has been identified in an individual undergoing hereditary cancer panel testing (LaDuca 2014). We consider this variant to be pathogenic. -

May 06, 2016

Clinical Genetics and Genomics, Karolinska University Hospital

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Lynch syndrome Pathogenic:2

May 13, 2020

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.Ile927AsnfsX8 variant in MSH6 has been reported in 1 individual undergoing familial cancer panel testing (LaDuca 2014). It has also been identified in 0.002% (2/113400) of European chromosomes by gnomAD (http://gnomad.broadinstitute.org). This variant is predicted to cause a frameshift, which alters the protein’s amino acid sequence beginning at position 927 and leads to a premature termination codon 8 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, this variant meets criteria to be classified as pathogenic for autosomal dominant Lynch syndrome. ACMG/AMP Criteria applied: PVS1, PM2. -

Feb 04, 2025

Department of Clinical Genetics, Copenhagen University Hospital, Rigshospitalet

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

PVS1; PS4_SUP; -

Hereditary cancer-predisposing syndrome Pathogenic:2

Jan 22, 2013

Ambry Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. -

Mar 27, 2020

Color Diagnostics, LLC DBA Color Health

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant inserts 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. To our knowledge, this variant has not been reported in individuals affected with hereditary cancer in the literature. This variant has been identified in 2/250978 chromosomes 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:1

Aug 21, 2023

Myriad Genetics, Inc.

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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

Breast and/or ovarian cancer Pathogenic:1

Jun 11, 2019

CZECANCA consortium

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Hereditary nonpolyposis colorectal neoplasms Pathogenic:1

Jun 14, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Ile927Asnfs*8) 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 (rs763978082, gnomAD 0.002%). This premature translational stop signal has been observed in individual(s) with clinical indications of hereditary cancer syndromes, such as Lynch syndrome (PMID: 24763289, 27601186). ClinVar contains an entry for this variant (Variation ID: 142168). For these reasons, this variant has been classified as Pathogenic. -

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: rs587782277; hg19: chr2-48027900;