chr2-47466792-G-A

Position:

• chr2-47466792-G-A

Variant summary

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

The NM_000251.3(MSH2):​c.1645G>A​(p.Val549Ile) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000274 in 1,461,322 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: MSH2 NM_000251.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:4
• Conservation: PhyloP100: 9.10

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.1645G>A	p.Val549Ile	missense_variant	10/16	ENST00000233146.7	NP_000242.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MSH2	ENST00000233146.7	c.1645G>A	p.Val549Ile	missense_variant	10/16	1	NM_000251.3	ENSP00000233146	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251230 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135826

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000880

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1461322 Hom.: 0 Cov.: 33 AF XY: 0.00000275 AC XY: 2 AN XY: 727004

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000270

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

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	May 21, 2023	The p.V549I variant (also known as c.1645G>A), located in coding exon 10 of the MSH2 gene, results from a G to A substitution at nucleotide position 1645. The valine at codon 549 is replaced by isoleucine, an amino acid with highly similar properties. 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 neutral (Jia X et al. Am J Hum Genet, 2021 Jan;108:163-175). 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. -
Uncertain significance, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Apr 24, 2023	This missense variant replaces valine with isoleucine at codon 549 of the MSH2 protein. Computational prediction 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). 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 been identified in 1/251230 chromosomes 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. -

Lynch syndrome 1 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Baylor Genetics

Sep 23, 2023

- -

Hereditary nonpolyposis colorectal neoplasms Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jul 31, 2022

This sequence change replaces valine, which is neutral and non-polar, with isoleucine, which is neutral and non-polar, at codon 549 of the MSH2 protein (p.Val549Ile). This variant is present in population databases (no rsID available, gnomAD 0.0009%). 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: 232658). Advanced modeling of experimental studies (such as gene expression, population dynamics, functional pathways, and cell-cycle effects in cell culture) performed at Invitae indicates that this missense variant is not expected to disrupt MSH2 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	0.13
BayesDel_addAF	Pathogenic	0.26	D
BayesDel_noAF	Pathogenic	0.14
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.47	T;.;.;.
Eigen	Pathogenic	0.91
Eigen_PC	Pathogenic	0.91
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.94	D;D;D;D
M_CAP	Benign	0.083	D
MetaRNN	Uncertain	0.67	D;D;D;D
MetaSVM	Uncertain	0.69	D
MutationAssessor	Uncertain	2.5	M;.;.;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.59	T
PROVEAN	Benign	-0.84	N;N;.;N
REVEL	Uncertain	0.60
Sift	Benign	0.045	D;D;.;T
Sift4G	Benign	0.11	T;T;.;T
Polyphen		0.98	D;.;.;D
Vest4		0.79
MutPred		0.48		Loss of MoRF binding (P = 0.1187);.;Loss of MoRF binding (P = 0.1187);Loss of MoRF binding (P = 0.1187);
MVP		0.85
MPC		0.032
ClinPred		0.93	D
GERP RS		6.0
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.51
gMVP		0.35

Splicing

Name	Calibrated prediction	Score	Prediction
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: rs876659905; hg19: chr2-47693931;