rs786204186

chr2-47795969-G-Achr2-47795969-G-Cchr2-47795969-G-T

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 0P and 3B. BP4_Moderate BP6

The NM_000179.3(MSH6):c.533G>A(p.Arg178His) variant causes a missense change. The variant allele was found at a frequency of 0.0000124 in 1,614,014 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. 15/20 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. R178C) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 33)
  • Exomes 𝑓: 0.000013 (1 hom.)
• Consequence: MSH6 NM_000179.3 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:10 B:2
• Conservation: PhyloP100: 3.59

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]

FBXO11 (HGNC:13590): (F-box protein 11) This gene encodes a member of the F-box protein family which is characterized by an approximately 40 amino acid motif, the F-box. The F-box proteins constitute one of the four subunits of ubiquitin protein ligase complex called SCFs (SKP1-cullin-F-box), which function in phosphorylation-dependent ubiquitination. The F-box proteins are divided into 3 classes: Fbws containing WD-40 domains, Fbls containing leucine-rich repeats, and Fbxs containing either different protein-protein interaction modules or no recognizable motifs. The protein encoded by this gene belongs to the Fbxs class. It can function as an arginine methyltransferase that symmetrically dimethylates arginine residues, and it acts as an adaptor protein to mediate the neddylation of p53, which leads to the suppression of p53 function. This gene is known to be down-regulated in melanocytes from patients with vitiligo, a skin disorder that results in depigmentation. Polymorphisms in this gene are associated with chronic otitis media with effusion and recurrent otitis media (COME/ROM), a hearing loss disorder, and the knockout of the homologous mouse gene results in the deaf mouse mutant Jeff (Jf), a single gene model of otitis media. Alternatively spliced transcript variants encoding distinct isoforms have been identified for this gene. [provided by RefSeq, Jun 2010]

ACMG classification

Verdict is Likely_benign. Variant got -3 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.16863826).
• BP6: Variant 2-47795969-G-A is Benign according to our data. Variant chr2-47795969-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 188269.We mark this variant Likely_benign, oryginal submissions are: {Uncertain_significance=9, Likely_benign=2}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MSH6	NM_000179.3	c.533G>A	p.Arg178His	missense_variant	3/10	ENST00000234420.11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MSH6	ENST00000234420.11	c.533G>A	p.Arg178His	missense_variant	3/10	1	NM_000179.3	P4

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152154 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

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 AF: 0.0000130 AC: 19 AN: 1461860 Hom.: 1 Cov.: 32 AF XY: 0.0000124 AC XY: 9 AN XY: 727232

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: 0.0000232

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000135

Gnomad4 OTH exome AF: 0.0000331

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152154 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 74326

Gnomad4 AFR AF: 0.0000241

Gnomad4 AMR AF: 0.00

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

Alfa AF: 0.0000244 Hom.: 0

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:10 Benign:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Lynch syndrome 5 Uncertain:2 Benign:1

Uncertain significance, criteria provided, single submitter	clinical testing	Mendelics	May 28, 2019	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Counsyl	Sep 07, 2016	- -
Likely benign, criteria provided, single submitter	clinical testing	Myriad Genetics, Inc.	Mar 28, 2023	This variant is considered likely benign. This variant is strongly associated with less severe personal and family histories of cancer, typical for individuals without pathogenic variants in this gene [PMID: 25085752]. -

not provided Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Quest Diagnostics Nichols Institute San Juan Capistrano	Oct 28, 2022	The frequency of this variant in the general population, 0.0000066 (1/152154 chromosomes, http://gnomad.broadinstitute.org), is uninformative in assessment of its pathogenicity. To the best of our knowledge, this variant has not been reported as a germline variant in individuals with an MSH6-related disorder in the published literature. 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. -
Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Oct 26, 2023	Not observed in large population cohorts (gnomAD); 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; This variant is associated with the following publications: (PMID: 22949379, 25224212) -

Hereditary cancer-predisposing syndrome Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Mar 16, 2023	The p.R178H variant (also known as c.533G>A), located in coding exon 3 of the MSH6 gene, results from a G to A substitution at nucleotide position 533. The arginine at codon 178 is replaced by histidine, an amino acid with highly similar properties. This amino acid position is not well 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. -
Uncertain significance, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	May 04, 2023	This missense variant replaces arginine with histidine at codon 178 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. -

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Nov 13, 2018

Variant summary: MSH6 c.533G>A (p.Arg178His) results in a non-conservative amino acid change located in the PWWP domain of the encoded protein sequence. Three of five in-silico tools predict a benign effect of the variant on protein function. The variant was absent in 246216 control chromosomes (gnomAD) . The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. To our knowledge, no occurrence of c.533G>A in individuals affected with Lynch Syndrome and no experimental evidence demonstrating its impact on protein function have been reported. Five clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -

Lynch syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

All of Us Research Program, National Institutes of Health

Jul 22, 2023

This missense variant replaces arginine with histidine at codon 178 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

Uncertain significance, no assertion criteria provided

clinical testing

Department of Pathology and Laboratory Medicine, Sinai Health System

-

The MSH6 p.Arg178His variant was not identified in the literature nor was it identified in the following databases: MutDB, UMD-LSDB, Insight Colon Cancer Gene Variant Database, Mismatch Repair Genes Variant Database, Insight Hereditary Tumors Database and the Zhejiang Colon Cancer Database. The variant was identified in dbSNP (ID: rs786204186) as “With uncertain significance allele”, ClinVar (as uncertain significance by Invitae, Ambry Genetics, Counsyl, and GeneDx), Clinvitae (4x as uncertain significance), Cosmic (1x in endometrial tissue as pathogenic (score 0.80). The variant was not identified in the 1000 Genomes Project, the NHLBI GO Exome Sequencing Project or the Exome Aggregation Consortium (August 8th 2016). The variant was identified with a co-occurring pathogenic BARD1 variant (p.Glu59AlafsX8) in one individual from our laboratory, increasing the likelihood that the p.Arg178His variant does not have clinical significance. The p.Arg178His residue is not conserved in mammals and computational analyses (PolyPhen-2, SIFT, AlignGVGD, BLOSUM, MutationTaster) provide inconsistent predictions regarding the impact to the protein; this information is not very predictive of pathogenicity. The variant occurs outside of the splicing consensus sequence and in silico or computational prediction software programs (SpliceSiteFinder, MaxEntScan, NNSPLICE, GeneSplicer, HumanSpliceFinder) 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. -

Endometrial carcinoma Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Baylor Genetics

Oct 22, 2023

- -

Hereditary nonpolyposis colorectal neoplasms Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Invitae

Dec 17, 2023

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.087
BayesDel_addAF	Benign	-0.063	T
BayesDel_noAF	Benign	-0.33
Cadd	Benign	23
Dann	Uncertain	1.0
DEOGEN2	Benign	0.28	T;T;.;T;T
Eigen	Benign	0.15
Eigen_PC	Uncertain	0.24
FATHMM_MKL	Uncertain	0.80	D
LIST_S2	Uncertain	0.94	D;D;D;D;D
M_CAP	Benign	0.039	D
MetaRNN	Benign	0.17	T;T;T;T;T
MetaSVM	Benign	-0.86	T
MutationAssessor	Benign	0.0	N;.;.;.;.
MutationTaster	Benign	1.0	D;D;D;D
PrimateAI	Benign	0.48	T
PROVEAN	Benign	-0.76	N;.;N;N;N
REVEL	Benign	0.13
Sift	Benign	0.22	T;.;T;T;T
Sift4G	Benign	0.17	T;T;T;D;T
Polyphen		0.83	P;.;.;.;.
Vest4		0.14
MVP		0.60
ClinPred		0.67	D
GERP RS		4.0
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.33
gMVP		0.25

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: rs786204186; hg19: chr2-48023108; COSMIC: COSV52286682; COSMIC: COSV52286682;