2-47482785-GA-GAA

Position:

• chr2-47482785-GA-GAA

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PVS1_Strong PM2 PP5_Very_Strong

The ENST00000233146.7(MSH2):​c.2647dupA​(p.Ile883fs) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,460,990 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: MSH2 ENST00000233146.7 frameshift
• Clinical Significance: Pathogenic reviewed by expert panel P:8 U:1
• Conservation: PhyloP100: 8.08

Genes affected

MSH2 (HGNC:7325): (mutS homolog 2) This locus is frequently mutated in hereditary nonpolyposis colon cancer (HNPCC). When cloned, it was discovered to be a human homolog of the E. coli mismatch repair gene mutS, consistent with the characteristic alterations in microsatellite sequences (RER+ phenotype) found in HNPCC. Two transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Apr 2012]

MSH2 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 14 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. There are 19 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 2-47482785-G-GA is Pathogenic according to our data. Variant chr2-47482785-G-GA is described in ClinVar as [Pathogenic]. Clinvar id is 91031.Status of the report is reviewed_by_expert_panel, 3 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MSH2	NM_000251.3	c.2647dupA	p.Ile883fs	frameshift_variant	16/16	ENST00000233146.7	NP_000242.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MSH2	ENST00000233146.7	c.2647dupA	p.Ile883fs	frameshift_variant	16/16	1	NM_000251.3	ENSP00000233146.2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1460990 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 726804

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: 9.00e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:8 Uncertain:1

Revision: reviewed by expert panel

Submissions by phenotype

not provided Pathogenic:3

Pathogenic, criteria provided, single submitter	clinical testing	Institute for Clinical Genetics, University Hospital TU Dresden, University Hospital TU Dresden	Feb 09, 2023	- -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Apr 22, 2019	This duplication causes a frameshift which changes an Isoleucine to an Asparagine at codon 883, and creates a premature stop codon at position 16 of the new reading frame. Even though nonsense-mediateddecay is not expected to occur due to the position of the variant, it is significant since the last 52 amino acids are no longer translated correctly and are replaced by 15 incorrect amino acids. This variant is predicted to cause loss ofnormal protein function through protein truncation. MSH2 Ile883AsnfsX16 has been observed in individuals with apersonal and/or family history suggestive of Lynch syndrome, including an individual with colon cancer demonstrating microsatellite instability (Hampel 2005, Bonadona 2011). Additionally, Wielders et al. (2017) found that MSH2 variants lacking the c-terminus severely destabilize MSH2/MSH6 interaction and result in increased microsatellite instability. Based on the currently available information, we consider this duplication to be pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Quest Diagnostics Nichols Institute San Juan Capistrano	Jul 08, 2021	This frameshift variant causes the premature termination of MSH2 protein synthesis. In the published literature, it has been reported in an individual with colorectal cancer with microsatellite instability (PMID: 15872200 (2005)). Based on the available information, this variant is classified as pathogenic. -

Lynch syndrome 1 Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Myriad Genetics, Inc.	Aug 09, 2023	This variant is considered pathogenic. This variant creates a frameshift predicted to result in premature protein truncation. -
Pathogenic, reviewed by expert panel	curation	International Society for Gastrointestinal Hereditary Tumours (InSiGHT)	Jun 13, 2018	This variant is before the cutoff (codon 888) and therefore Class 5 -

Hereditary cancer-predisposing syndrome Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Jan 28, 2022	This variant inserts 1 nucleotide in exon 16 of the MSH2 gene, creating a frameshift and premature translation stop signal, creating a frameshift and premature translation stop signal in the last coding exon. This variant is predicted to escape nonsense-mediated decay and be expressed as a truncated protein. To our knowledge, functional studies have not been reported for this variant. This variant has been reported in individuals affected with Lynch syndrome (PMID: 15872200, 21642682). This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). Loss of MSH2 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	Feb 19, 2018	The c.2647dupA pathogenic mutation, located in coding exon 16 of the MSH2 gene, results from a duplication of A at nucleotide position 2647, causing a translational frameshift with a predicted alternate stop codon (p.I883Nfs*16). This mutation has been reported in a 57 year old male with colon cancer which was MSI-H and showed loss of MSH6 protein expression (Hampel H et al. N Engl J Med. 2005 May 5;352(18):1851-60). In addition to the clinical data presented in the literature, this alteration is expected to result in loss of function by premature protein truncation. As such, this alteration is interpreted as a disease-causing mutation. -

Hereditary nonpolyposis colorectal neoplasms Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Dec 29, 2023

This sequence change creates a premature translational stop signal (p.Ile883Asnfs*16) in the MSH2 gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 52 amino acid(s) of the MSH2 protein. This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individual(s) with colorectal cancer (PMID: 15872200, 29967336). ClinVar contains an entry for this variant (Variation ID: 91031). This variant disrupts the MSH6 and MSH3 interaction domains of the MSH2 protein, as well as the helix-turn-helix domain, which are important for proper dimerization and normal protein functioning (PMID: 9774676, 18822302, 17531815). While functional studies have not been performed to directly test the effect of this variant on MSH2 protein function, this suggests that disruption of this region of the protein is causative of disease. This variant disrupts a region of the MSH2 protein in which other variant(s) (p.Leu888Cysfs*4) have been determined to be pathogenic (PMID: 8640829, 9222765, 21879275; Invitae). This suggests that this is a clinically significant region of the protein, and that variants that disrupt it are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

Endometrial carcinoma Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

Department of Pathology and Laboratory Medicine, Sinai Health System

-

The MSH2 p.Ile883AsnfsX16 variant was identified in 4 of 1490 proband chromosomes (frequency: 0.003) from French and American individuals or families with Lynch Syndrome or CRC (Bonadona 2011, Hampel 2005). The variant was also identified in dbSNP (ID: rs63750145) “With Pathogenic allele”, ClinVar (classified as uncertain significance, reviewed by an expert panel (2015)), Clinvitae (2x), UMD-LSDB (15x causal), Insight Colon Cancer Gene Variant Database (1x), Mismatch Repair Genes Variant Database (1x), Insight Hereditary Tumors Database (1x),and was not identified in Genesight-COGR, Cosmic, Zhejiang Colon Cancer Database, the 1000 Genomes Project, the NHLBI GO Exome Sequencing Project or the Exome Aggregation Consortium (August 8th 2016) control databases. The c.2647dupA variant is predicted to cause a frameshift, which alters the protein's amino acid sequence beginning at codon 883 and leads to a premature stop codon 16 codons downstream. This alteration is then predicted to result in a truncated or absent protein and loss of function. Loss of function variants of the MSH2 gene are an established mechanism of disease in Lynch syndrome and this is the type of variant expected to cause the disorder; however, variants in the last exon of the gene and stop codon or nonsense mutations in this region may not be subjected to nonsense mediated RNA decay. Although further study would be required to validate this hypothesis and it is currently not possible to determine whether or not this might influence the severity of the disorder. In summary, based on the above information the clinical significance of this variant cannot be determined with certainty at this time. This variant is classified as a variant of uncertain significance. -

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: rs63750084; hg19: chr2-47709924;