2-47806627-T-G

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 4P and 2B. PM1 PM2 BP4_Moderate

The NM_000179.3(MSH6):c.3977T>G(p.Met1326Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000186 in 1,611,686 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. M1326T) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: MSH6 NM_000179.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:5
• Conservation: PhyloP100: 0.649

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 Uncertain_significance. Variant got 2 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 8 benign, 17 uncertain in NM_000179.3
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.24925348).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MSH6	NM_000179.3	c.3977T>G	p.Met1326Arg	missense_variant	9/10	ENST00000234420.11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MSH6	ENST00000234420.11	c.3977T>G	p.Met1326Arg	missense_variant	9/10	1	NM_000179.3	P4

Frequencies

GnomAD3 genomes AF: 0.00000658 AC: 1 AN: 151964 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

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: 0.000479

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1459722 Hom.: 0 Cov.: 35 AF XY: 0.00000275 AC XY: 2 AN XY: 726260

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: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.00000658 AC: 1 AN: 151964 Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1 AN XY: 74194

Gnomad4 AFR AF: 0.00

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: 0.000479

Bravo AF: 0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Mar 16, 2023	The p.M1326R variant (also known as c.3977T>G), located in coding exon 9 of the MSH6 gene, results from a T to G substitution at nucleotide position 3977. The methionine at codon 1326 is replaced by arginine, an amino acid with similar properties. This alteration was identified in an individual with core-binding factor acute myeloid leukemia from a cohort of children and adolescents (n=1120) with cancer that underwent whole-genome, whole-exome, or both types of sequencing (Zhang J et al. N. Engl. J. Med. 2015 Dec;373:2336-2346). This amino acid position is not well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. 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	Jun 07, 2023	This missense variant replaces methionine with arginine at codon 1326 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 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

All of Us Research Program, National Institutes of Health

Aug 15, 2023

This missense variant replaces methionine with arginine at codon 1326 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 Lynch syndrome. This variant has been observed in an individual with acute myeloid leukemia (PMID: 26580448). 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 provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Aug 16, 2023

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant does not alter protein structure/function; Observed in an individual with acute myeloid leukemia (Zhang et al., 2015); This variant is associated with the following publications: (PMID: 12019211, 17531815, 21120944, 26580448, 35451682) -

Hereditary nonpolyposis colorectal neoplasms Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Oct 20, 2023

This sequence change replaces methionine, which is neutral and non-polar, with arginine, which is basic and polar, at codon 1326 of the MSH6 protein (p.Met1326Arg). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with acute myeloid leukemia (PMID: 26580448). ClinVar contains an entry for this variant (Variation ID: 455312). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt MSH6 protein function. 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	Benign	0.14
BayesDel_addAF	Uncertain	0.13	D
BayesDel_noAF	Uncertain	-0.050
Cadd	Benign	19
Dann	Benign	0.81
Eigen	Benign	-0.48
Eigen_PC	Benign	-0.29
FATHMM_MKL	Uncertain	0.91	D
M_CAP	Benign	0.040	D
MetaRNN	Benign	0.25	T;T;T;T;T
MetaSVM	Benign	-0.80	T
MutationTaster	Benign	1.0	D;D;D;D
PrimateAI	Benign	0.47	T
Sift4G	Benign	0.51	T;T;T;T;T
Polyphen		0.0010	.;.;.;B;.
Vest4		0.52
MutPred		0.41		.;.;.;Gain of disorder (P = 0.027);.;
MVP		0.88
ClinPred		0.069	T
GERP RS		2.4
Varity_R		0.31
gMVP		0.59

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: rs757089977; hg19: chr2-48033766;