rs587779254

chr2-47801146-G-Achr2-47801146-G-C

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM1 PM5 PP3_Moderate

The NM_000179.3(MSH6):c.3163G>A(p.Ala1055Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000112 in 1,610,080 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic 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. A1055P) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: 𝑓 0.000020 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000010 (0 hom.)
• Consequence: MSH6 NM_000179.3 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:8 B:1
• Conservation: PhyloP100: 7.90

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_pathogenic. Variant got 6 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 5 benign, 17 uncertain in NM_000179.3
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr2-47801146-G-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 126892.Status of the report is reviewed_by_expert_panel, 3 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.846

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MSH6	NM_000179.3	c.3163G>A	p.Ala1055Thr	missense_variant	4/10	ENST00000234420.11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MSH6	ENST00000234420.11	c.3163G>A	p.Ala1055Thr	missense_variant	4/10	1	NM_000179.3	P4

Frequencies

GnomAD3 genomes AF: 0.0000197 AC: 3 AN: 152144 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000724

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

GnomAD3 exomes AF: 0.0000163 AC: 4 AN: 245304 Hom.: 0 AF XY: 0.0000225 AC XY: 3 AN XY: 133440

Gnomad AFR exome AF: 0.0000633

Gnomad AMR exome AF: 0.0000580

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000546

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000103 AC: 15 AN: 1457936 Hom.: 0 Cov.: 34 AF XY: 0.00000965 AC XY: 7 AN XY: 725412

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000447

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000756

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000809

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.0000197 AC: 3 AN: 152144 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74334

Gnomad4 AFR AF: 0.0000724

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

Bravo AF: 0.0000264

ExAC AF: 0.00000824 AC: 1

Asia WGS AF: 0.000289 AC: 1 AN: 3478

EpiCase AF: 0.0000545

EpiControl AF: 0.0000593

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:8 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Lynch syndrome 5 Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Myriad Genetics, Inc.	Mar 29, 2023	This variant is classified as a variant of uncertain significance as there is insufficient evidence to determine its impact on protein function and/or cancer risk. -
Uncertain significance, criteria provided, single submitter	clinical testing	Counsyl	Dec 08, 2015	- -

Hereditary cancer-predisposing syndrome Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Apr 07, 2022	The p.A1055T variant (also known as c.3163G>A), located in coding exon 4 of the MSH6 gene, results from a G to A substitution at nucleotide position 3163. The alanine at codon 1055 is replaced by threonine, an amino acid with similar properties. This variant was reported to co-occur with a pathogenic APC deletion in an individual with colorectal cancer and numerous (at least 100) colorectal polyps (Ricker CN et al. Cancer, 2017 Oct;123:3732-3743). This alteration was also identified in an individual diagnosed with colorectal cancer at 30 and a glioblastoma diagnosed at 42. This alteration was identified in cis with c.2087T>C and in trans with c.2098C>T (Suerink M et al. Genet Med, 2019 12;21:2706-2712). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious 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	Mar 17, 2023	This missense variant replaces alanine with threonine at codon 1055 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 individuals affected with colorectal cancer, however, both individuals also had a co-occurring pathogenic variant (PMID: 28640387, 29596542). This variant has been identified in 7/276690 chromosomes 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

Center for Genomic Medicine, Rigshospitalet, Copenhagen University Hospital

Feb 06, 2024

- -

Endometrial carcinoma;C1833477:Lynch syndrome 5;C5399763:Mismatch repair cancer syndrome 1 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Oct 31, 2018

- -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Jul 27, 2023

In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Reported in an individual with colorectal cancer and hundreds of colorectal polyps, who also carried an APC pathogenic variant (Ricker et al., 2017); This variant is associated with the following publications: (PMID: 23359684, 26333163, 23621914, 24362816, 27556954, 29596542, 17531815, 21120944, 28640387) -

Endometrial carcinoma Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Baylor Genetics

Oct 25, 2023

- -

Hereditary nonpolyposis colorectal neoplasms Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Invitae

Dec 31, 2023

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.53
BayesDel_addAF	Pathogenic	0.26	D
BayesDel_noAF	Pathogenic	0.32
Cadd	Benign	23
Dann	Uncertain	1.0
Eigen	Uncertain	0.57
Eigen_PC	Uncertain	0.45
FATHMM_MKL	Pathogenic	0.99	D
M_CAP	Pathogenic	0.31	D
MetaRNN	Pathogenic	0.85	D;D;D;D;D;D
MetaSVM	Pathogenic	0.98	D
MutationTaster	Benign	1.0	D;D;D;D
PrimateAI	Uncertain	0.60	T
Sift4G	Uncertain	0.050	T;D;D;D;D;T
Polyphen		1.0	.;.;.;D;.;.
Vest4		0.47
MutPred		0.78		.;.;.;Loss of stability (P = 0.084);.;.;
MVP		0.97
ClinPred		0.61	D
GERP RS		3.3
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.8
Varity_R		0.59
gMVP		0.85

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs587779254; hg19: chr2-48028285; COSMIC: COSV52276308; COSMIC: COSV52276308;