rs1553352377

chr2-47414269-G-Achr2-47414269-G-Cchr2-47414269-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM1 PM2 PP3

The NM_000251.3(MSH2):c.793G>A(p.Val265Ile) variant causes a missense, splice region change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V265F) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 29)
• Consequence: MSH2 NM_000251.3 missense, splice_region
• Scores: Splicing: ADA: 0.9993
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 4.94

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 5 ACMG points.

• PM1: In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 10 benign, 14 uncertain in NM_000251.3
• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. No scorers claiming Uncertain. Scorers claiming Benign: max_spliceai.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MSH2	NM_000251.3	c.793G>A	p.Val265Ile	missense_variant, splice_region_variant	5/16	ENST00000233146.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MSH2	ENST00000233146.7	c.793G>A	p.Val265Ile	missense_variant, splice_region_variant	5/16	1	NM_000251.3	P1

Frequencies

GnomAD3 genomes Cov.: 29

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 29

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Mar 21, 2018	The p.V265I variant (also known as c.793G>A) is located in coding exon 5 of the MSH2 gene. The valine at codon 265 is replaced by isoleucine, an amino acid with highly similar properties. This change occurs in the first base pair of coding exon 5. This amino acid position is well conserved in available vertebrate species. Using the BDGP and ESEfinder splice site prediction tools, this alteration is predicted to weaken the efficiency of the native splice acceptor site; however, direct evidence is unavailable. In addition, the in silico prediction for this alteration is inconclusive. In addition, this alteration is predicted to be benign by MAPP-MMR in silico analyses (Chao EC et al. Hum. Mutat. 2008 Jun;29:852-60). Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -
Uncertain significance, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	May 23, 2023	This missense variant replaces valine with isoleucine at codon 265 of the MSH2 protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). This variant does not impact MSH2 function in a 6-thioguanine sensitivity assay in haploid human cells (internally defined LOF score threshold <= -1.32, PMID: 33357406). To our knowledge, this variant has not been reported in individuals affected with MSH2-related disorders 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. -

Hereditary nonpolyposis colorectal neoplasms Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Dec 12, 2023

This sequence change replaces valine, which is neutral and non-polar, with isoleucine, which is neutral and non-polar, at codon 265 of the MSH2 protein (p.Val265Ile). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with clinical features of MSH2-related conditions (PMID: 21520333). ClinVar contains an entry for this variant (Variation ID: 652775). Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Not Available"; PolyPhen-2: "Benign"; Align-GVGD: "Not Available". The isoleucine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. 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	Benign	0.068
BayesDel_addAF	Uncertain	0.12	D
BayesDel_noAF	Uncertain	-0.060
Cadd	Benign	23
Dann	Uncertain	1.0
DEOGEN2	Benign	0.41	T;.;.;.
Eigen	Benign	0.029
Eigen_PC	Benign	0.20
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Benign	0.85	D;D;D;D
M_CAP	Benign	0.054	D
MetaRNN	Benign	0.33	T;T;T;T
MetaSVM	Uncertain	-0.23	T
MutationAssessor	Benign	1.3	L;.;.;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Benign	0.44	T
PROVEAN	Benign	-0.13	N;N;.;N
REVEL	Uncertain	0.36
Sift	Benign	0.11	T;T;.;T
Sift4G	Benign	0.34	T;T;.;T
Polyphen		0.0010	B;.;.;B
Vest4		0.49
MutPred		0.51		Gain of catalytic residue at L270 (P = 0.055);.;Gain of catalytic residue at L270 (P = 0.055);Gain of catalytic residue at L270 (P = 0.055);
MVP		0.89
MPC		0.0077
ClinPred		0.79	D
GERP RS		4.3
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.16
gMVP		0.17

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.94
SpliceAI score (max)		0.030		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: rs1553352377; hg19: chr2-47641408;