rs876660900

Positions:

• chr2-47475219-C-A
• chr2-47475219-C-G
• chr2-47475219-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1 PM2 PM5 PP3_Moderate

The NM_000251.3(MSH2):​c.1954C>A​(p.Pro652Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 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. P652H) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: MSH2 NM_000251.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 7.40

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 Likely_pathogenic. Variant got 8 ACMG points.

• PM1: In a region_of_interest Interaction with EXO1 (size 70) in uniprot entity MSH2_HUMAN there are 24 pathogenic changes around while only 4 benign (86%) in NM_000251.3
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr2-47475220-C-A is described in Lovd as [Likely_pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.932

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MSH2	NM_000251.3	c.1954C>A	p.Pro652Thr	missense_variant	12/16	ENST00000233146.7	NP_000242.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MSH2	ENST00000233146.7	c.1954C>A	p.Pro652Thr	missense_variant	12/16	1	NM_000251.3	ENSP00000233146.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 32

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	Color Diagnostics, LLC DBA Color Health	Dec 11, 2023	This missense variant replaces proline with threonine at codon 652 of the MSH2 protein. Computational prediction suggests that this variant may have deleterious impact on protein structure and function (internally defined REVEL score threshold >= 0.7, 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). A different variant affecting the same codon, c.1955C>A (p.Pro652His), is considered to be disease-causing (ClinVar variation ID: 90823), suggesting that this position is important for the protein function. 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	Sep 28, 2015	The p.P652T variant (also known as c.1954C>A), located in coding exon 12 of the MSH2 gene, results from a C to A substitution at nucleotide position 1954. The proline at codon 652 is replaced by threonine, an amino acid with highly similar properties. While this exact alteration has not been reported in the literature, an alteration at the same codon, p.P652H (c.1955C>A), has been classified as likely pathogenic by multifactorial analysis, which integrates the following lines of evidence to produce a quantitative likelihood of pathogenicity: in silico prediction models, segregation with disease, clinical phenotype including tumor characteristics, mutation co-occurrence, and functional assay results (Thompson B et al. Nat Genet. 2014 Feb;46(2):107-15; available at [www.insight-group.org/variants/classifications/]).The p.P652T variant was not reported in population based cohorts in the following databases: Database of Single Nucleotide Polymorphisms (dbSNP), NHLBI Exome Sequencing Project (ESP), and 1000 Genomes Project. In the ESP, this variant was not observed in 6503 samples (13006 alleles) with coverage at this position. To date, this alteration has been detected with an allele frequency of approximately 0.002% (greater than 65000 alleles tested) in our clinical cohort. This amino acid position is highly conserved in available vertebrate species. This alteration is predicted to be probably damaging and tolerated by PolyPhen and SIFT in silico analyses, respectively. In addition, this alteration is predicted to be benign by MAPP-MMR in silico analyses (Chao E et al. Hum Mutat. 2008 Jun;29(6):852-60). Since supporting evidence is limited at this time, the clinical significance of p.P652T remains unclear. -

Hereditary nonpolyposis colorectal neoplasms Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 17, 2020

This sequence change replaces proline with threonine at codon 652 of the MSH2 protein (p.Pro652Thr). The proline residue is highly conserved and there is a small physicochemical difference between proline and threonine. This variant is not present in population databases (ExAC no frequency). 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. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). This variant has not been reported in the literature in individuals with MSH2-related disease. ClinVar contains an entry for this variant (Variation ID: 234174). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.48
BayesDel_addAF	Pathogenic	0.41	D
BayesDel_noAF	Pathogenic	0.35
CADD	Uncertain	26
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.81	D;.;.;.
Eigen	Pathogenic	0.74
Eigen_PC	Pathogenic	0.74
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.96	D;D;D;D
M_CAP	Uncertain	0.11	D
MetaRNN	Pathogenic	0.93	D;D;D;D
MetaSVM	Uncertain	0.25	D
MutationAssessor	Uncertain	2.8	M;.;.;.
PrimateAI	Uncertain	0.63	T
PROVEAN	Uncertain	-4.2	D;D;.;D
REVEL	Pathogenic	0.81
Sift	Benign	0.86	T;T;.;T
Sift4G	Benign	0.47	T;T;.;T
Polyphen		1.0	D;.;.;D
Vest4		0.98
MutPred		0.84		Gain of catalytic residue at P652 (P = 0.0834);.;Gain of catalytic residue at P652 (P = 0.0834);Gain of catalytic residue at P652 (P = 0.0834);
MVP		0.96
MPC		0.033
ClinPred		1.0	D
GERP RS		6.0
Varity_R		0.62
gMVP		0.89

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: rs876660900; hg19: chr2-47702358;