2-47791123-G-C

Position:

• chr2-47791123-G-C

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP3 PP5

The NM_000179.3(MSH6):​c.457G>C​(p.Gly153Arg) variant causes a missense, splice region change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency: Genomes: not found (cov: 33)
• Consequence: MSH6 NM_000179.3 missense, splice_region
• Scores: Splicing: ADA: 0.9999
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2 U:2
• Conservation: PhyloP100: 7.12

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]

MSH6 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.782
• PP5: Variant 2-47791123-G-C is Pathogenic according to our data. Variant chr2-47791123-G-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 525678.We mark this variant Likely_pathogenic, oryginal submissions are: {Uncertain_significance=2, Likely_pathogenic=2}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MSH6	NM_000179.3	c.457G>C	p.Gly153Arg	missense_variant, splice_region_variant	2/10	ENST00000234420.11	NP_000170.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MSH6	ENST00000234420.11	c.457G>C	p.Gly153Arg	missense_variant, splice_region_variant	2/10	1	NM_000179.3	ENSP00000234420.5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 33

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:2 Uncertain:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Lynch syndrome 5 Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Myriad Genetics, Inc.

Sep 11, 2024

This variant is considered likely pathogenic. mRNA analysis has demonstrated abnormal mRNA splicing occurs [Myriad internal data]. -

Hereditary cancer-predisposing syndrome Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Sep 11, 2024

The c.457G>C variant (also known as p.G153R), located in coding exon 2 of the MSH6 gene, results from a G to C substitution at nucleotide position 457. The amino acid change results in glycine to arginine at codon 153, an amino acid with dissimilar properties. However, this change occurs in the last base pair of coding exon 2, which makes it likely to have some effect on normal mRNA splicing. In silico splice site analysis predicts that this alteration may weaken the native splice donor site. RNA studies have demonstrated that this alteration results in abnormal splicing in the set of samples tested (Ambry internal data). In addition, this variant has been identified in a proband whose Lynch syndrome-associated tumor demonstrated loss of MSH6 expression by immunohistochemistry (Ambry internal data). This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). This nucleotide position is highly conserved in available vertebrate species. Based on the majority of available evidence to date, this variant is likely to be pathogenic. -

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

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

Jul 21, 2023

Variant summary: MSH6 c.457G>C (p.Gly153Arg) results in a non-conservative amino acid change located in the PWWP domain (IPR000313) of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. As the variant alters the last conserved nucleotide of exon 2 adjacent to the canonical splice donor site, several computational tools predict a significant impact on normal splicing: One predicts the variant abolishes a canonical 5' splicing donor site, two predict the variant weakens the 5' donor site, and one does not predict a significant impact on splicing. These predictions have yet to be confirmed by functional studies in the published literature, however a ClinVar submitter cites internal data from RNA studies stating that this alteration results in abnormal splicing (Ambry internal data). The variant was absent in 251366 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.457G>C in individuals affected with Hereditary Nonpolyposis Colorectal Cancer/Lynch syndrome and no experimental evidence demonstrating its impact on protein function have been reported in the literature. Two submitters have cited clinical-significance assessments for this variant to ClinVar after 2014. One submitter, citing both internal RNA splicing data and an internal observation of the variant in a proband with a Lynch syndrome-associated tumor with loss of MSH6 expression by immunohistochemistry, classified the variant as likely pathogenic, and one submitter classified the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as VUS-possibly pathogenic. -

Hereditary nonpolyposis colorectal neoplasms Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Sep 23, 2017

This sequence change replaces glycine with arginine at codon 153 of the MSH6 protein (p.Gly153Arg). The glycine residue is moderately conserved and there is a moderate physicochemical difference between glycine and arginine. This variant also falls at the last nucleotide of exon 2 of the MSH6 coding sequence, which is part of the consensus splice site for this exon. 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. Nucleotide substitutions within the consensus splice site are relatively common causes of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site, but this prediction has not been confirmed by published transcriptional studies. Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). This variant has not been reported in the literature in individuals with MSH6-related disease. This variant is not present in population databases (ExAC no frequency). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.87
BayesDel_addAF	Pathogenic	0.20	D
BayesDel_noAF	Uncertain	0.050
CADD	Pathogenic	33
DANN	Pathogenic	1.0
DEOGEN2	Uncertain	0.45	T;T;.;T;T
Eigen	Pathogenic	0.78
Eigen_PC	Pathogenic	0.71
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.89	D;D;D;D;D
M_CAP	Uncertain	0.22	D
MetaRNN	Pathogenic	0.78	D;D;D;D;D
MetaSVM	Uncertain	0.25	D
MutationAssessor	Pathogenic	2.9	M;.;.;.;.
PrimateAI	Uncertain	0.67	T
PROVEAN	Uncertain	-2.7	D;.;D;D;D
REVEL	Pathogenic	0.70
Sift	Uncertain	0.010	D;.;D;D;D
Sift4G	Uncertain	0.023	D;D;D;D;D
Polyphen		1.0	D;.;.;.;.
Vest4		0.46
MutPred		0.56		Gain of MoRF binding (P = 0.0074);.;.;.;.;
MVP		0.87
ClinPred		0.99	D
GERP RS		4.4
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		2.8
Varity_R		0.94
gMVP		0.64

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.95
SpliceAI score (max)		0.43		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.43		Position offset: 0

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs1060502885; hg19: chr2-48018262;