rs587782706

chr2-47799433-G-Achr2-47799433-G-Cchr2-47799433-G-T

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PM1 PM2 PM5 PP3_Strong PP5

The NM_000179.3(MSH6):c.1450G>A(p.Glu484Lys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,870 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 12/20 in silico tools predict a damaging 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. E484Q) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: MSH6 NM_000179.3 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:2
• Conservation: PhyloP100: 9.97

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 Pathogenic. Variant got 11 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 17 uncertain in NM_000179.3
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr2-47799433-G-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 142768.We mark this variant Likely_pathogenic, oryginal submissions are: {Pathogenic=1, Likely_pathogenic=1, Uncertain_significance=2}.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.953
• PP5: Variant 2-47799433-G-A is Pathogenic according to our data. Variant chr2-47799433-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 216297.We mark this variant Likely_pathogenic, oryginal submissions are: {Likely_pathogenic=1, Uncertain_significance=2}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MSH6	NM_000179.3	c.1450G>A	p.Glu484Lys	missense_variant	4/10	ENST00000234420.11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MSH6	ENST00000234420.11	c.1450G>A	p.Glu484Lys	missense_variant	4/10	1	NM_000179.3	P4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461870 Hom.: 0 Cov.: 34 AF XY: 0.00000138 AC XY: 1 AN XY: 727230

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: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1 Uncertain:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Hereditary cancer-predisposing syndrome Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Jun 07, 2022

The p.E484K variant (also known as c.1450G>A), located in coding exon 4 of the MSH6 gene, results from a G to A substitution at nucleotide position 1450. The glutamic acid at codon 484 is replaced by lysine, an amino acid with similar properties. This variant has been reported in an individual with MSI-H colorectal cancer that showed loss of MSH6 protein by immunohistochemistry; this individual also met Amsterdam criteria for Lynch syndrome (Dámaso E et al. Cancers (Basel), 2020 Jul;12:). Based on internal structural analysis, this variant is deleterious, is moderately destabilizing to the local structure, and is more destabilizing than nearby likely pathogenic variants (Ambry internal data). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Based on the majority of available evidence to date, this variant is likely to be pathogenic. -

Lynch syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

All of Us Research Program, National Institutes of Health

Jun 26, 2023

This missense variant replaces glutamic acid with lysine at codon 484 of the MSH6 protein. Computational prediction suggests that this variant may have deleterious impact on protein structure and function (internally defined REVEL score threshold >= 0.7, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in an individual affected with colorectal cancer that exhibited microsatellite instability and loss of MSH6 protein by immunohistochemistry analysis (PMID: 32635641). 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

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Oct 05, 2023

This sequence change replaces glutamic acid, which is acidic and polar, with lysine, which is basic and polar, at codon 484 of the MSH6 protein (p.Glu484Lys). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with clinical features of Lynch syndrome (PMID: 32635641; Invitae). ClinVar contains an entry for this variant (Variation ID: 216297). An algorithm developed specifically for the MSH6 gene suggests that this missense change is likely to be deleterious (PMID: 23621914). This variant disrupts the p.Glu484 amino acid residue in MSH6. Other variant(s) that disrupt this residue have been observed in individuals with MSH6-related conditions (Invitae), which suggests that this may be a clinically significant amino acid residue. 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	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.49	D
BayesDel_noAF	Pathogenic	0.46
Cadd	Pathogenic	27
Dann	Pathogenic	1.0
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.97
FATHMM_MKL	Pathogenic	0.99	D
M_CAP	Pathogenic	0.36	D
MetaRNN	Pathogenic	0.95	D;D;D;D;D
MetaSVM	Pathogenic	0.99	D
MutationTaster	Benign	1.0	D;D;D;D
PrimateAI	Pathogenic	0.84	D
Sift4G	Pathogenic	0.0	D;D;D;D;D
Polyphen		1.0	.;.;D;.;.
Vest4		0.95
MutPred		0.79		.;.;Gain of methylation at E484 (P = 0.0046);.;.;
MVP		0.99
ClinPred		1.0	D
GERP RS		5.3
Varity_R		0.99
gMVP		0.88

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: rs587782706; hg19: chr2-48026572;