2-47783318-C-T

Variant names:

• chr2-47783318-C-T
• rs756589186
• NM_000179.3:c.85C>T

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_001406799.1(MSH6):​c.-244C>T variant causes a 5 prime UTR premature start codon gain 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. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: MSH6 NM_001406799.1 5_prime_UTR_premature_start_codon_gain
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:4
• Conservation: PhyloP100: 0.0830

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.15783924).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MSH6	NM_000179.3	c.85C>T	p.Arg29Cys	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.85C>T	p.Arg29Cys	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: 0.000224 Hom.: 0

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:2

Sep 01, 2021

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.R29C variant (also known as c.85C>T), located in coding exon 1 of the MSH6 gene, results from a C to T substitution at nucleotide position 85. The arginine at codon 29 is replaced by cysteine, an amino acid with highly dissimilar properties. This amino acid position is poorly conserved in available vertebrate species. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Dec 05, 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 cysteine at codon 29 of the MSH6 protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has not been reported in individuals affected with MSH6-related disorders 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. -

Lynch syndrome 5 Uncertain:1

May 20, 2023

Neuberg Centre For Genomic Medicine, NCGM

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The observed missense variant c.85C>T(p.Arg29Cys) in the MSH6 gene has not been reported previously as a pathogenic variant nor as a benign variant, to our knowledge. This variant is reported with the allele frequency 0.003% in the gnomAD Exomes. This variant has been reported to the ClinVar database as Uncertain Significance by multiple submitters. However, no details are available for independent assessment. The amino acid Arginine at position 29 is changed to a Cysteine changing protein sequence and it might alter its composition and physico- chemical properties. Multiple lines of computational evidence (Polyphen - Benign, SIFT - Tolerated and MutationTaster - Polymorphism) predict no damaging effect on protein structure and function for this variant. The residue is conserved by GERP++ and PhyloP across 100 vertebrates. For these reasons, this variant has been classified as Uncertain Significance. -

Hereditary nonpolyposis colorectal neoplasms Uncertain:1

Sep 11, 2018

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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 (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has not been reported in the literature in individuals with MSH6-related disease. ClinVar contains an entry for this variant (Variation ID: 485850). This variant is not present in population databases (ExAC no frequency). This sequence change replaces arginine with cysteine at codon 29 of the MSH6 protein (p.Arg29Cys). The arginine residue is weakly conserved and there is a large physicochemical difference between arginine and cysteine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.23
BayesDel_addAF	Benign	-0.053	T
BayesDel_noAF	Benign	-0.31
CADD	Benign	17
DANN	Uncertain	0.98
DEOGEN2	Benign	0.28	.;T;T
Eigen	Benign	-1.1
Eigen_PC	Benign	-1.2
FATHMM_MKL	Benign	0.0079	N
LIST_S2	Uncertain	0.87	D;D;D
M_CAP	Pathogenic	0.71	D
MetaRNN	Benign	0.16	T;T;T
MetaSVM	Benign	-0.82	T
MutationAssessor	Benign	0.55	N;N;.
PrimateAI	Uncertain	0.73	T
PROVEAN	Benign	-1.5	N;N;.
REVEL	Benign	0.17
Sift	Benign	0.094	T;D;.
Sift4G	Uncertain	0.055	T;D;T
Polyphen		0.0	.;B;.
Vest4		0.17
MutPred		0.26		Loss of MoRF binding (P = 0.0032);Loss of MoRF binding (P = 0.0032);Loss of MoRF binding (P = 0.0032);
MVP		0.57
ClinPred		0.15	T
GERP RS		-3.1
RBP_binding_hub_radar		0.92
RBP_regulation_power_radar		2.7
Varity_R		0.11
gMVP		0.46

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: rs756589186; hg19: chr2-48010457;