chr2-47783311-G-T

Variant names:

• chr2-47783311-G-T
• rs1395190094
• NM_000179.3:c.78G>T

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 4P and 2B. PM1 PM2 BP4_Moderate

The NM_000179.3(MSH6):​c.78G>T​(p.Arg26Ser) 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 benign outcome for this variant. 15/22 in silico tools predict a benign 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. R26T) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 33)
• Consequence: MSH6 NM_000179.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 0.150
• Publications: 1 publications found

Genes affected

MSH6 (HGNC:7329): (mutS homolog 6) This gene encodes a member of the DNA mismatch repair MutS family. In E. coli, the MutS protein helps in the recognition of mismatched nucleotides prior to their repair. A highly conserved region of approximately 150 aa, called the Walker-A adenine nucleotide binding motif, exists in MutS homologs. The encoded protein heterodimerizes with MSH2 to form a mismatch recognition complex that functions as a bidirectional molecular switch that exchanges ADP and ATP as DNA mismatches are bound and dissociated. Mutations in this gene may be associated with hereditary nonpolyposis colon cancer, colorectal cancer, and endometrial cancer. Transcripts variants encoding different isoforms have been described. [provided by RefSeq, Jul 2013]

MSH6 Gene-Disease associations (from GenCC):

• Lynch syndrome

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: G2P, ClinGen, Orphanet
• Lynch syndrome 5

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Laboratory for Molecular Medicine, Genomics England PanelApp
• mismatch repair cancer syndrome 1

  Inheritance: AR Classification: DEFINITIVE, SUPPORTIVE Submitted by: ClinGen, Orphanet
• mismatch repair cancer syndrome 3

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Laboratory for Molecular Medicine, Labcorp Genetics (formerly Invitae), G2P
• ovarian cancer

  Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp
• malignant pancreatic neoplasm

  Inheritance: AD Classification: MODERATE Submitted by: Genomics England PanelApp
• Muir-Torre syndrome

  Inheritance: AD Classification: MODERATE, SUPPORTIVE Submitted by: Genomics England PanelApp, Orphanet
• rhabdomyosarcoma

  Inheritance: AR Classification: MODERATE Submitted by: Genomics England PanelApp
• breast cancer

  Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics
• prostate cancer

  Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics
• hereditary breast carcinoma

  Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

ACMG classification

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 19 benign, 44 uncertain in NM_000179.3
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.17736918).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MSH6	NM_000179.3	c.78G>T	p.Arg26Ser	missense_variant	Exon 1 of 10	ENST00000234420.11	NP_000170.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MSH6	ENST00000234420.11	c.78G>T	p.Arg26Ser	missense_variant	Exon 1 of 10	1	NM_000179.3	ENSP00000234420.5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 33

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:2

May 01, 2025

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.R26S variant (also known as c.78G>T), located in coding exon 1 of the MSH6 gene, results from a G to T substitution at nucleotide position 78. The arginine at codon 26 is replaced by serine, an amino acid with dissimilar properties. This amino acid position is conserved. In addition, this alteration is predicted to be tolerated by in silico analysis. Based on the available evidence, the clinical significance of this variant remains unclear. -

Dec 04, 2023

Color Diagnostics, LLC DBA Color Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces arginine with serine at codon 26 of the MSH6 protein. Computational prediction tools and conservation analyses are inconclusive regarding the impact of this variant on protein structure and function. Splice site prediction tools suggest that this variant may not impact RNA splicing. To our knowledge, functional studies have not been performed for this variant. This variant has not been reported in individuals affected with hereditary cancer 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

Sep 15, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine, which is basic and polar, with serine, which is neutral and polar, at codon 26 of the MSH6 protein (p.Arg26Ser). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with MSH6-related conditions. ClinVar contains an entry for this variant (Variation ID: 920304). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is not expected to disrupt MSH6 protein function with a negative 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	Benign	0.13
BayesDel_addAF	Benign	-0.028	T
BayesDel_noAF	Benign	-0.28
CADD	Benign	13
DANN	Benign	0.75
DEOGEN2	Benign	0.23	.;T;T
Eigen	Benign	-1.2
Eigen_PC	Benign	-1.1
FATHMM_MKL	Benign	0.0062	N
LIST_S2	Benign	0.74	T;T;T
M_CAP	Pathogenic	0.92	D
MetaRNN	Benign	0.18	T;T;T
MetaSVM	Benign	-0.86	T
MutationAssessor	Benign	0.69	N;N;.
PhyloP100		0.15
PrimateAI	Uncertain	0.79	T
PROVEAN	Benign	0.73	N;N;.
REVEL	Benign	0.19
Sift	Benign	0.67	T;T;.
Sift4G	Benign	0.92	T;T;T
Polyphen		0.0010	.;B;.
Vest4		0.35
MutPred		0.34		Gain of glycosylation at R26 (P = 0.0055);Gain of glycosylation at R26 (P = 0.0055);Gain of glycosylation at R26 (P = 0.0055);
MVP		0.50
ClinPred		0.043	T
GERP RS		0.53
PromoterAI		-0.14	Neutral
RBP_binding_hub_radar		0.92
RBP_regulation_power_radar		2.1
Varity_R		0.21
gMVP		0.46
Mutation Taster		=97/3	polymorphism

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

Other links and lift over

dbSNP: rs1395190094; hg19: chr2-48010450; COSMIC: COSV99315061; COSMIC: COSV99315061;