rs368988823

chr2-47478458-T-Achr2-47478458-T-C

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1 PM2 PP3_Strong

The NM_000251.3(MSH2):c.2397T>A(p.Asn799Lys) variant causes a missense change involving the alteration of a non-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. N799S) has been classified 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:3
• Conservation: PhyloP100: 0.650

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 Likely_pathogenic. Variant got 8 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 11 benign, 14 uncertain in NM_000251.3
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.978

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MSH2	NM_000251.3	c.2397T>A	p.Asn799Lys	missense_variant	14/16	ENST00000233146.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MSH2	ENST00000233146.7	c.2397T>A	p.Asn799Lys	missense_variant	14/16	1	NM_000251.3	P1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 31

ExAC AF: 0.00000824 AC: 1

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	Oct 31, 2023	This missense variant replaces asparagine with lysine at codon 799 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). In a large breast cancer case-control study, this variant was reported in 1/60466 cases and 1/53461 unaffected controls (PMID: 33471991). 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	Apr 20, 2021	The p.N799K variant (also known as c.2397T>A), located in coding exon 14 of the MSH2 gene, results from a T to A substitution at nucleotide position 2397. The asparagine at codon 799 is replaced by lysine, an amino acid with similar properties. This variant was reported in 1/60,466 breast cancer cases and in 1/53,461 controls (Dorling et al. N Engl J Med. 2021 02;384:428-439). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Hereditary nonpolyposis colorectal neoplasms Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jun 23, 2023

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. Advanced modeling performed at Invitae incorporating data from internal and/or published experimental studies (PMID: 33357406) indicates that this missense variant is not expected to disrupt MSH2 function. ClinVar contains an entry for this variant (Variation ID: 939657). This variant has not been reported in the literature in individuals affected with MSH2-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces asparagine, which is neutral and polar, with lysine, which is basic and polar, at codon 799 of the MSH2 protein (p.Asn799Lys). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.45	D
BayesDel_noAF	Uncertain	-0.020
Cadd	Benign	22
Dann	Uncertain	1.0
DEOGEN2	Pathogenic	0.90	D;.;.;.
Eigen	Uncertain	0.48
Eigen_PC	Uncertain	0.32
FATHMM_MKL	Uncertain	0.92	D
LIST_S2	Uncertain	0.94	D;D;D;D
M_CAP	Pathogenic	0.38	D
MetaRNN	Pathogenic	0.98	D;D;D;D
MetaSVM	Uncertain	0.57	D
MutationAssessor	Pathogenic	3.6	H;.;.;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.78	T
PROVEAN	Pathogenic	-5.8	D;D;.;D
REVEL	Pathogenic	0.78
Sift	Pathogenic	0.0	D;D;.;D
Sift4G	Uncertain	0.0020	D;D;.;D
Polyphen		1.0	D;.;.;D
Vest4		0.98
MutPred		0.94		Gain of ubiquitination at N799 (P = 0.0311);.;Gain of ubiquitination at N799 (P = 0.0311);Gain of ubiquitination at N799 (P = 0.0311);
MVP		0.96
MPC		0.034
ClinPred		1.0	D
GERP RS		1.6
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.98
gMVP		0.90

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs368988823; hg19: chr2-47705597;