2-47806651-G-C

Variant names:

• chr2-47806651-G-C
• rs267608122
• NM_000179.3:c.4001G>C

Variant summary

Our verdict is Pathogenic. Variant got 16 ACMG points: 16P and 0B. PM2 PM5 PP3_Strong PP5_Very_Strong

The NM_000179.3(MSH6):​c.4001G>C​(p.Arg1334Pro) variant causes a missense, splice region change. The variant allele was found at a frequency of 0.000000687 in 1,455,180 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R1334Q) has been classified as Pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: MSH6 NM_000179.3 missense, splice_region
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:6
• Conservation: PhyloP100: 4.10

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 16 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr2-47806651-G-A is described in Lovd as [Pathogenic].
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 2-47806651-G-C is Pathogenic according to our data. Variant chr2-47806651-G-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 233214.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr2-47806651-G-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MSH6	NM_000179.3	c.4001G>C	p.Arg1334Pro	missense_variant, splice_region_variant	Exon 9 of 10	ENST00000234420.11	NP_000170.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MSH6	ENST00000234420.11	c.4001G>C	p.Arg1334Pro	missense_variant, splice_region_variant	Exon 9 of 10	1	NM_000179.3	ENSP00000234420.5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.87e-7 AC: 1 AN: 1455180 Hom.: 0 Cov.: 34 AF XY: 0.00000138 AC XY: 1 AN XY: 724216

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: 0.00

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:6

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Lynch syndrome Pathogenic:3

Jan 12, 2022

Diagnostic Molecular Genetics Laboratory, Memorial Sloan Kettering Cancer Center

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The heterozygous germline variant, MSH6 c.4001G>C changes an Arginine to Proline at amino acid position 1334 (p.Arg1334Pro) and affects the last nucleotide of exon 9. This variant is absent from large population databases (1000 Genomes, ESP, and Broad ExAc). Computational prediction tools (SpliceSiteFinder, MaxEntScan, NNSPLICE and GeneSplicer) predict a complete loss of the intron 9 canonical splice donor site. Our functional study by RNA analysis (DMG internal data) demonstrated that this variant completely abolished normal splicing and caused exon 9 skipping, which is expected to lead to a prematurely truncated or abnormal protein. Our results indicate that this variant likely contributes to cancer predisposition through disruption of normal splicing, and is classified as likely pathogenic. -

Aug 11, 2023

Clinical Genetics Laboratory, Skane University Hospital Lund

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

May 13, 2022

Genetics and Molecular Pathology, SA Pathology

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Lynch syndrome 5 Pathogenic:1

Mar 10, 2023

Myriad Genetics, Inc.

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is considered likely pathogenic. This variant has been reported in multiple individuals with clinical features of gene-specific disease [PMID: 36691871]. mRNA analysis has demonstrated abnormal mRNA splicing occurs [PMID: 36691871]. -

Hereditary nonpolyposis colorectal neoplasms Pathogenic:1

Sep 23, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine, which is basic and polar, with proline, which is neutral and non-polar, at codon 1334 of the MSH6 protein (p.Arg1334Pro). RNA analysis indicates that this missense change induces altered splicing and likely disrupts the C-terminus of the protein. This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individuals with clinical features of Lynch syndrome (PMID: 36691871; internal data). ClinVar contains an entry for this variant (Variation ID: 233214). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Studies have shown that this missense change results in skipping of exon 9 and introduces a new termination codon (PMID: 36691871). However the mRNA is not expected to undergo nonsense-mediated decay. This variant disrupts the c.4001G nucleotide in the MSH6 gene. Other variant(s) that disrupt this nucleotide have been determined to be pathogenic (PMID: 10508506, 21836479; internal data). This suggests that this nucleotide is clinically significant, and that variants that disrupt this position are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

Hereditary cancer-predisposing syndrome Pathogenic:1

Oct 31, 2024

Ambry Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.4001G>C pathogenic mutation (also known as p.R1334P), located in coding exon 9 of the MSH6 gene, results from a G to C substitution at nucleotide position 4001. The amino acid change results in arginine to proline at codon 1334, an amino acid with dissimilar properties. However, this change occurs in the last base pair of coding exon 9, which makes it likely to have some effect on normal mRNA splicing. This variant has been identified in a proband who met Amsterdam II criteria for Lynch syndrome and tumor demonstrated high microsatellite instability with loss of MSH6 expression by immunohistochemistry (Yang C et al. Mol Genet Genomic Med, 2023 Feb;11:e2104). This nucleotide position is well conserved in available vertebrate species. This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). In silico splice site analysis predicts that this alteration will 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). Another alteration impacting the same donor site (c.4001G>A) has been shown to have a similar impact on splicing identified in several probands, one of whom has a Lynch syndrome-associated tumor that demonstrated loss of MSH6 expression by immunohistochemistry (Ambry internal data). Based on the supporting evidence, this alteration is interpreted as a disease-causing mutation. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.96
BayesDel_addAF	Pathogenic	0.37	D
BayesDel_noAF	Pathogenic	0.29
CADD	Pathogenic	29
DANN	Uncertain	0.99
DEOGEN2	Benign	0.29	.;.;T;D;.
Eigen	Uncertain	0.63
Eigen_PC	Pathogenic	0.69
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.90	.;D;D;D;D
M_CAP	Uncertain	0.23	D
MetaRNN	Pathogenic	0.79	D;D;D;D;D
MetaSVM	Uncertain	0.46	D
MutationAssessor	Benign	1.7	.;.;.;L;.
PrimateAI	Benign	0.45	T
PROVEAN	Uncertain	-4.0	.;D;.;D;D
REVEL	Uncertain	0.63
Sift	Uncertain	0.027	.;D;.;D;D
Sift4G	Benign	0.064	T;T;D;D;T
Polyphen		0.97	.;.;.;D;.
Vest4		0.75
MutPred		0.53		.;.;.;Loss of MoRF binding (P = 0.0047);.;
MVP		0.96
ClinPred		0.98	D
GERP RS		6.0
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.92
gMVP		0.84

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	1.0
SpliceAI score (max)		0.89		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.89		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: rs267608122; hg19: chr2-48033790;