rs587779162

chr2-47410173-G-Achr2-47410173-G-Cchr2-47410173-G-T

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PM2 PM5 PP3_Strong PP5

The NM_000251.3(MSH2):c.446G>A(p.Gly149Asp) variant causes a missense change. The variant allele was found at a frequency of 0.00000657 in 152,176 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G149S) has been classified as Likely benign.

• Frequency: Genomes: 𝑓 0.0000066 (0 hom., cov: 31)
• Consequence: MSH2 NM_000251.3 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2 U:2
• Conservation: PhyloP100: 6.20

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 9 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr2-47410172-G-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 1740769.Status of the report is criteria_provided_single_submitter, 1 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.945
• PP5: Variant 2-47410173-G-A is Pathogenic according to our data. Variant chr2-47410173-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 91099.We mark this variant Likely_pathogenic, oryginal submissions are: {Likely_pathogenic=2, Uncertain_significance=1}. Variant chr2-47410173-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MSH2	NM_000251.3	c.446G>A	p.Gly149Asp	missense_variant	3/16	ENST00000233146.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MSH2	ENST00000233146.7	c.446G>A	p.Gly149Asp	missense_variant	3/16	1	NM_000251.3	P1

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152176 Hom.: 0 Cov.: 31

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000655

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome Cov.: 32

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152176 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 74332

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.0000655

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.00000378

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:2 Uncertain:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Lynch syndrome 1 Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Myriad Genetics, Inc.

Jul 27, 2023

This variant is considered likely pathogenic. Functional studies indicate this variant impacts protein function [PMID: 33357406]. This variant is expected to disrupt protein structure [Myriad internal data]. -

Hereditary cancer-predisposing syndrome Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Apr 17, 2023

The p.G149D variant (also known as c.446G>A), located in coding exon 3 of the MSH2 gene, results from a G to A substitution at nucleotide position 446. The glycine at codon 149 is replaced by aspartic acid, an amino acid with similar properties. This variant was identified in a proband with colorectal cancer diagnosed at age 37 (Chao EC et al. Hum. Mutat. 2008 Jun;29:852-60). This variant has been identified in a proband whose Lynch syndrome-associated tumor demonstrated high microsatellite instability and partial loss of MSH2/MSH6 expression by immunohistochemistry (Ambry internal data). In a massively parallel cell-based functional assay testing susceptibility to a DNA damaging agent, 6-thioguanine (6-TG), this variant was reported to be functionally deleterious (Jia X et al. Am J Hum Genet, 2021 Jan;108:163-175). This amino acid position is highly conserved through mammals but not in all available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). Based on the majority of available evidence to date, this variant is likely to be pathogenic. -

Carcinoma of colon Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

Department of Pathology and Laboratory Medicine, Sinai Health System

-

The MSH2 p.Gly149Asp variant was not identified in the literature nor was it identified in the UMD-LSDB database. The variant was also identified in dbSNP (ID: rs587779162) as "With Uncertain significance allele", and in ClinVar (classified as uncertain significance by InSight). The variant was not identified in the following control databases: the Exome Aggregation Consortium (August 8th 2016), or the Genome Aggregation Database (Feb 27, 2017). The p.Gly149 residue is conserved in mammals but not in more distantly related organisms, and four out of five computational analyses (PolyPhen-2, SIFT, AlignGVGD, BLOSUM, MutationTaster) suggest that the aspartic acid variant may impact the protein; however, this information is not predictive enough to assume pathogenicity. The variant occurs outside of the splicing consensus sequence and in silico or computational prediction software programs (SpliceSiteFinder, MaxEntScan, NNSPLICE, GeneSplicer) do not predict a difference in splicing. 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. -

Hereditary nonpolyposis colorectal neoplasms Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Dec 15, 2023

This sequence change replaces glycine, which is neutral and non-polar, with aspartic acid, which is acidic and polar, at codon 149 of the MSH2 protein (p.Gly149Asp). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with colorectal cancer (PMID: 18383312). ClinVar contains an entry for this variant (Variation ID: 91099). Advanced modeling performed at Invitae incorporating data from internal and/or published experimental studies (PMID: 33357406) indicates that this missense variant is expected to disrupt MSH2 function with a positive predictive value of 95%. 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	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.42	D
BayesDel_noAF	Pathogenic	0.36
Cadd	Pathogenic	28
Dann	Uncertain	1.0
DEOGEN2	Uncertain	0.78	D;T;.;.;.
Eigen	Uncertain	0.38
Eigen_PC	Uncertain	0.38
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.91	D;D;D;D;D
M_CAP	Benign	0.084	D
MetaRNN	Pathogenic	0.95	D;D;D;D;D
MetaSVM	Benign	-0.30	T
MutationAssessor	Uncertain	2.1	M;.;.;.;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.68	T
PROVEAN	Uncertain	-2.8	D;D;D;.;D
REVEL	Pathogenic	0.82
Sift	Uncertain	0.0020	D;D;D;.;D
Sift4G	Uncertain	0.0040	D;D;D;.;D
Polyphen		0.99	D;.;.;.;D
Vest4		0.77
MutPred		0.85		Loss of catalytic residue at V150 (P = 0.0622);.;.;Loss of catalytic residue at V150 (P = 0.0622);Loss of catalytic residue at V150 (P = 0.0622);
MVP		0.96
MPC		0.026
ClinPred		0.95	D
GERP RS		4.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.97
gMVP		0.90

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.060		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: rs587779162; hg19: chr2-47637312;