2-47800209-C-G

Variant names:

• chr2-47800209-C-G
• rs587781739
• NM_000179.3:c.2226C>G

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM1 PP3_Strong

The NM_000179.3(MSH6):​c.2226C>G​(p.Asn742Lys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000684 in 1,461,876 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. N742S) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000068 (0 hom.)
• Consequence: MSH6 NM_000179.3 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:6 B:1
• Conservation: PhyloP100: 1.69
• Publications: 1 publications found

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]

FBXO11 Gene-Disease associations (from GenCC):

• intellectual developmental disorder with dysmorphic facies and behavioral abnormalities

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, G2P

ACMG classification

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 4 benign, 39 uncertain in NM_000179.3
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.978

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MSH6	NM_000179.3	c.2226C>G	p.Asn742Lys	missense_variant	Exon 4 of 10	ENST00000234420.11	NP_000170.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MSH6	ENST00000234420.11	c.2226C>G	p.Asn742Lys	missense_variant	Exon 4 of 10	1	NM_000179.3	ENSP00000234420.5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000399 AC: 1 AN: 250894 AF XY: 0.00000737

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000544

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000684 AC: 10 AN: 1461876 Hom.: 0 Cov.: 34 AF XY: 0.00000688 AC XY: 5 AN XY: 727234

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44722

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26134

East Asian (EAS) AF: 0.000227 AC: 9 AN: 39698

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53414

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1112006

Other (OTH) AF: 0.00 AC: 0 AN: 60396

GnomAD4 genome Cov.: 32

ExAC AF: 0.00000824 AC: 1

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:6 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:2

Mar 31, 2025

Color Diagnostics, LLC DBA Color Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces asparagine with lysine at codon 742 of the MSH6 protein. Computational prediction suggests that this variant may have deleterious impact on protein structure and function. To our knowledge, functional studies have not been reported for this variant. This variant has been reported in individuals affected with unspecified cancers in the literature (PMID: 31386297). In a pancreatic cancer case-control study, this variant was observed in both affected cases and unaffected controls (p value= 0.140; PMID: 32980694). This variant has been identified in 1/250894 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. -

May 09, 2024

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.N742K variant (also known as c.2226C>G), located in coding exon 4 of the MSH6 gene, results from a C to G substitution at nucleotide position 2226. The asparagine at codon 742 is replaced by lysine, an amino acid with similar properties. This variant was observed in an individual with early onset-breast cancer amongst a cohort of 1781 non-Ashkenazi Jewish individuals undergoing BRCA1/2 gene testing based on a personal history of breast cancer (Tung N et al. Cancer, 2015 Jan;121:25-33). This amino acid position is highly conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Based on the available evidence, the clinical significance of this variant remains unclear. -

Endometrial carcinoma;C1833477:Lynch syndrome 5;C5436807:Mismatch repair cancer syndrome 3 Uncertain:1

May 15, 2024

Fulgent Genetics, Fulgent Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Uncertain:1

Oct 21, 2022

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Observed in individuals with cancer, not otherwise specified, who had germline genetic testing that included analysis of Lynch syndrome-associated genes (Kiyozumi et al., 2019); This variant is associated with the following publications: (PMID: 17531815, 21120944, 31386297) -

Hereditary nonpolyposis colorectal neoplasms Uncertain:1

Jan 21, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces asparagine, which is neutral and polar, with lysine, which is basic and polar, at codon 742 of the MSH6 protein (p.Asn742Lys). This variant is present in population databases (rs587781739, gnomAD 0.006%). This missense change has been observed in individual(s) with an unspecified cancer and/or biliary tract cancer (PMID: 31386297, 36243179). ClinVar contains an entry for this variant (Variation ID: 141430). 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 expected to disrupt MSH6 protein function with a positive predictive value of 95%. 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. -

Hereditary breast ovarian cancer syndrome Uncertain:1

May 01, 2019

Cancer Genomics Group, Japanese Foundation For Cancer Research

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: research

- -

not specified Benign:1

Sep 04, 2024

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

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: MSH6 c.2226C>G (p.Asn742Lys) results in a non-conservative amino acid change located in the core domain (IPR007696) of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 6.2e-06 in 1607196 control chromosomes, predominantly at a frequency of 0.0002 within the East Asian subpopulation in the gnomAD database. However, the variant was reported in some East Asian subpopulations with an even higher allele frequency, e.g. in the Japanese, with an allele frequency of 0.00094 (in the jMorp database [PMID: 33179747]). This frequency is about 6.7-fold higher than the maximum expected for a pathogenic variant in MSH6 causing Hereditary Nonpolyposis Colorectal Cancer (0.00014), suggesting the variant could be a benign polymorphism. The variant, c.2226C>G, has been reported in the literature in individuals affected with various cancers, including biliary tract- and breast cancer (e.g. Kiyozumi_2019, Okawa_2023, Dorling_2021), however it was also found in several controls greater than 60-years-old, who did not have a personal or family history of cancer (Okawa_2023). To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publications have been ascertained in the context of this evaluation (PMID: 31386297, 36243179, 33471991). ClinVar contains an entry for this variant (Variation ID: 141430). Based on the evidence outlined above, the variant was classified as likely benign. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Uncertain	0.085	D
BayesDel_noAF	Uncertain	0.050
CADD	Benign	19
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.87	.;.;D;D;.
Eigen	Uncertain	0.58
Eigen_PC	Uncertain	0.48
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Uncertain	0.93	.;D;D;D;D
M_CAP	Pathogenic	0.48	D
MetaRNN	Pathogenic	0.98	D;D;D;D;D
MetaSVM	Pathogenic	0.91	D
MutationAssessor	Pathogenic	3.7	.;.;H;.;.
PhyloP100		1.7
PrimateAI	Uncertain	0.62	T
PROVEAN	Pathogenic	-5.8	.;D;D;.;D
REVEL	Pathogenic	0.90
Sift	Uncertain	0.0020	.;D;D;.;D
Sift4G	Uncertain	0.0040	D;D;D;D;D
Polyphen		1.0	.;.;D;.;.
Vest4		0.98
MutPred		0.87		.;.;Loss of catalytic residue at N742 (P = 0.005);.;.;
MVP		0.97
ClinPred		0.98	D
GERP RS		3.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.5
Varity_R		0.96
gMVP		0.85
Mutation Taster		=12/88	disease causing

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

Other links and lift over

dbSNP: rs587781739; hg19: chr2-48027348;