rs1553369781

Positions:

• chr2-47478442-T-A
• chr2-47478442-T-C
• chr2-47478442-T-G

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_000251.3(MSH2):​c.2381T>A​(p.Ile794Lys) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency: Genomes: not found (cov: 31)
• Consequence: MSH2 NM_000251.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:5
• Conservation: PhyloP100: 3.83

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MSH2	NM_000251.3	c.2381T>A	p.Ile794Lys	missense_variant	14/16	ENST00000233146.7	NP_000242.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MSH2	ENST00000233146.7	c.2381T>A	p.Ile794Lys	missense_variant	14/16	1	NM_000251.3	ENSP00000233146.2

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 31

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Nov 20, 2019	This missense variant replaces isoleucine with lysine at codon 794 of the MSH2 protein. Computational prediction tool is inconclusive regarding the impact of this variant on protein structure and function (internally defined REVEL score threshold 0.5 < inconclusive < 0.7, PMID: 27666373). Splice site prediction tools suggest that this variant may not impact RNA splicing. To our knowledge, functional studies have not been performed for this variant. This variant has not been reported in individuals affected with hereditary cancer in the literature. This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -
Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Feb 09, 2023	The p.I794K variant (also known as c.2381T>A), located in coding exon 14 of the MSH2 gene, results from a T to A substitution at nucleotide position 2381. The isoleucine at codon 794 is replaced by lysine, an amino acid with dissimilar properties. This amino acid position is not well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Lynch syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

All of Us Research Program, National Institutes of Health

Apr 15, 2023

This missense variant replaces isoleucine with lysine at codon 794 of the MSH2 protein. Computational prediction tool is inconclusive regarding the impact of this variant on protein structure and function (internally defined REVEL score threshold 0.5 < inconclusive < 0.7, PMID: 27666373). Splice site prediction tools suggest that this variant may not impact RNA splicing. To our knowledge, functional studies have not been performed for this variant. This variant has not been reported in individuals affected with hereditary cancer in the literature. This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Quest Diagnostics Nichols Institute San Juan Capistrano

Nov 05, 2024

The MSH2 c.2381T>A (p.Ile794Lys) variant has not been reported in individuals with MSH2-related conditions in the published literature. A screening assay based on cell survival in response to 6-thioguanine treatment showed that this variant has an inconclusive effect on DNA mismatch repair function (PMID: 33357406 (2021)). It also has not been reported in large, multi-ethnic general populations (Genome Aggregation Database, http://gnomad.broadinstitute.org). Analysis of this variant using bioinformatics tools for the prediction of the effect of amino acid changes on protein structure and function yielded conflicting predictions that this variant is benign or damaging. Based on the available information, we are unable to determine the clinical significance of this variant. -

Hereditary nonpolyposis colorectal neoplasms Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Dec 08, 2023

This sequence change replaces isoleucine, which is neutral and non-polar, with lysine, which is basic and polar, at codon 794 of the MSH2 protein (p.Ile794Lys). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with MSH2-related conditions. ClinVar contains an entry for this variant (Variation ID: 455561). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt MSH2 protein function with a negative predictive value of 80%. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.40
BayesDel_addAF	Pathogenic	0.17	D
BayesDel_noAF	Uncertain	0.010
CADD	Uncertain	25
DANN	Benign	0.95
DEOGEN2	Uncertain	0.72	D;.;.;.
Eigen	Uncertain	0.22
Eigen_PC	Uncertain	0.31
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Uncertain	0.94	D;D;D;D
M_CAP	Benign	0.029	D
MetaRNN	Uncertain	0.60	D;D;D;D
MetaSVM	Benign	-0.83	T
MutationAssessor	Benign	1.2	L;.;.;.
PrimateAI	Uncertain	0.61	T
PROVEAN	Uncertain	-3.9	D;D;.;D
REVEL	Pathogenic	0.65
Sift	Benign	0.12	T;T;.;T
Sift4G	Benign	0.21	T;T;.;T
Polyphen		0.19	B;.;.;P
Vest4		0.59
MutPred		0.68		Gain of disorder (P = 0.0037);.;Gain of disorder (P = 0.0037);Gain of disorder (P = 0.0037);
MVP		0.81
MPC		0.0081
ClinPred		0.68	D
GERP RS		5.3
Varity_R		0.63
gMVP		0.76

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: rs1553369781; hg19: chr2-47705581;