2-47783484-C-T

Variant names:

• chr2-47783484-C-T
• rs878853717
• NM_000179.3:c.251C>T

Variant summary

Our verdict is Likely benign. The variant received -1 ACMG points: 2P and 3B. PM1 BP4_Moderate BP6

The NM_000179.3(MSH6):​c.251C>T​(p.Ala84Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000117 in 1,279,590 control chromosomes in the GnomAD database, with no homozygous occurrence. 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A84P) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.000012 (0 hom.)
• Consequence: MSH6 NM_000179.3 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:6 B:2
• Conservation: PhyloP100: -0.545
• Publications: 2 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: Likely_benign. The variant received -1 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 6 benign, 39 uncertain in NM_000179.3
• BP4: Computational evidence support a benign effect (MetaRNN=0.07794097).
• BP6: Variant 2-47783484-C-T is Benign according to our data. Variant chr2-47783484-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 237159.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MSH6	NM_000179.3	c.251C>T	p.Ala84Val	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.251C>T	p.Ala84Val	missense_variant	Exon 1 of 10	1	NM_000179.3	ENSP00000234420.5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.0000117 AC: 15 AN: 1279590 Hom.: 0 Cov.: 34 AF XY: 0.0000145 AC XY: 9 AN XY: 621294

African (AFR) AF: 0.00 AC: 0 AN: 24890

American (AMR) AF: 0.00 AC: 0 AN: 17614

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 18278

East Asian (EAS) AF: 0.00 AC: 0 AN: 30468

South Asian (SAS) AF: 0.00 AC: 0 AN: 61678

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 44134

Middle Eastern (MID) AF: 0.000414 AC: 2 AN: 4830

European-Non Finnish (NFE) AF: 0.0000127 AC: 13 AN: 1024952

Other (OTH) AF: 0.00 AC: 0 AN: 52746

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:6 Benign:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Uncertain:2

Dec 04, 2020

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed in large population cohorts (Lek 2016); In silico analysis, which includes protein predictors and evolutionary conservation, supports that this variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

Jul 10, 2024

Quest Diagnostics Nichols Institute San Juan Capistrano

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The MSH6 c.251C>T (p.Ala84Val) variant has been reported in the published literature in individuals with breast cancer (PMID: 35449176 (2022)) and colorectal cancer (PMID: 34271781 (2021)). This variant has not been reported in large, multi-ethnic general populations (Genome Aggregation Database, http://gnomad.broadinstitute.org). Analysis of this variant using bioinformatics tools for the prediction of the effect of amino acid changes on protein structure and function yielded predictions that this variant is benign. Based on the available information, we are unable to determine the clinical significance of this variant. -

Hereditary cancer-predisposing syndrome Uncertain:1 Benign:1

Sep 28, 2017

Ambry Genetics

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

May 08, 2024

Color Diagnostics, LLC DBA Color Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces alanine with valine at codon 84 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

Jul 23, 2024

Molecular Pathology, Peter Maccallum Cancer Centre

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Lynch syndrome Uncertain:1

Jun 11, 2024

All of Us Research Program, National Institutes of Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces alanine with valine at codon 84 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. -

Malignant tumor of breast Uncertain:1

-

Department of Pathology and Laboratory Medicine, Sinai Health System

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

The MSH6 p.Ala84Val variant was not identified in the literature nor was it identified in the UMD-LSDB database. The variant was identified in dbSNP (ID: rs878853717) as “With Uncertain significance allele”, ClinVar (classified as uncertain significance by Invitae and likely benign by Ambry Genetics). 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.Ala84 residue is not conserved in mammals and 5 of 5 computational analyses (PolyPhen-2, SIFT, AlignGVGD, BLOSUM, MutationTaster) do not suggest a high likelihood of impact to the protein; however, this information is not predictive enough to rule out pathogenicity. The variant occurs outside of the splicing consensus sequence and 4 of 4 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 Benign:1

Jan 15, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.082
BayesDel_addAF	Benign	-0.21	T
BayesDel_noAF	Benign	-0.54
CADD	Benign	6.1
DANN	Benign	0.97
DEOGEN2	Benign	0.22	T;T
Eigen	Benign	-1.3
Eigen_PC	Benign	-1.4
FATHMM_MKL	Benign	0.0031	N
LIST_S2	Benign	0.46	T;T
M_CAP	Pathogenic	0.50	D
MetaRNN	Benign	0.078	T;T
MetaSVM	Benign	-0.83	T
MutationAssessor	Benign	-0.55	N;.
PhyloP100		-0.55
PrimateAI	Uncertain	0.70	T
PROVEAN	Benign	0.28	N;.
REVEL	Benign	0.17
Sift	Benign	0.40	T;.
Sift4G	Benign	0.31	T;T
Polyphen		0.0	B;.
Vest4		0.065
MutPred		0.13		Loss of glycosylation at P82 (P = 0.0737);.;
MVP		0.40
ClinPred		0.062	T
GERP RS		-3.3
PromoterAI		-0.021	Neutral
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.2
Varity_R		0.029
gMVP		0.21
Mutation Taster		=99/1	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: rs878853717; hg19: chr2-48010623; COSMIC: COSV105093212;