rs876661171

chr2-47806438-TTTTC-Tchr2-47806438-TTTTC-TTTTCTTTC

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP5

The NM_000179.3(MSH6):c.3802-7_3802-4del variant causes a splice polypyrimidine tract, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,744 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: MSH6 NM_000179.3 splice_polypyrimidine_tract, intron
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:4 U:1
• Conservation: PhyloP100: 0.0270

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 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 2-47806438-TTTTC-T is Pathogenic according to our data. Variant chr2-47806438-TTTTC-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 234703.We mark this variant Likely_pathogenic, oryginal submissions are: {Likely_pathogenic=3, Uncertain_significance=1, Pathogenic=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MSH6	NM_000179.3	c.3802-7_3802-4del		splice_polypyrimidine_tract_variant, intron_variant		ENST00000234420.11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MSH6	ENST00000234420.11	c.3802-7_3802-4del		splice_polypyrimidine_tract_variant, intron_variant		1	NM_000179.3	P4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 250970 Hom.: 0 AF XY: 0.00000737 AC XY: 1 AN XY: 135712

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 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: 0.00000137 AC: 2 AN: 1461744 Hom.: 0 AF XY: 0.00000138 AC XY: 1 AN XY: 727170

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000252

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

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:4 Uncertain:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Hereditary cancer-predisposing syndrome Pathogenic:2

Likely pathogenic, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Apr 05, 2019	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Ambry Genetics	Sep 21, 2023	The c.3802-7_3802-4delTCTT intronic variant, located in intron 8 of the MSH6 gene, results from a deletion of 4 nucleotides (TCTT) 7 nucleotides upstream of coding exon 9 in the MSH6 gene. This nucleotide region is well conserved in available vertebrate species. This variant segregated with Lynch syndrome-associated disease in four affected members of one family and has been identified in probands whose Lynch syndrome-associated tumor demonstrated loss of MSH6 expression by immunohistochemistry (Ambry internal data). In silico splice site analysis predicts that this alteration may weaken the native splice acceptor site. RNA studies have demonstrated that this alteration results in abnormal splicing in the set of samples tested (Ambry internal data). This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). Based on the majority of available evidence to date, this variant is likely to be pathogenic. -

not provided Pathogenic:1 Uncertain:1

Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Jul 10, 2018	This variant is denoted MSH6 c.3802-7_3802-4delTCTT or IVS8-7_IVS8-4delTCTT and consists of a deletion of four nucleotides at the -4 through -7 positions in intron 8 of the MSH6 gene. The normal sequence with the bases that are deleted in brackets is tctt[deltctt]aagG, where the capital letters are exonic and lowercase are intronic. Using alternate nomenclature, this variant may be defined as c.3802-13_3802-10delTTTC. In silico analyses, which include splice predictors and evolutionary conservation, are inconsistent in their assessment as to whether or not the variant is damaging. This variant was not observed at a significant allele frequency in large population cohorts (Lek 2016).This variant has not, to our knowledge, been published in the literature as either a pathogenic germline variant or a benign polymorphism. Based on the currently available information, we consider MSH6 c.3802-7_3802-4delTCTT to be a variant of uncertain significance. -
Likely pathogenic, criteria provided, single submitter	clinical testing	Mayo Clinic Laboratories, Mayo Clinic	Jul 28, 2022	PP1, PP4, PP5, PM2, PS3_supporting -

Hereditary nonpolyposis colorectal neoplasms Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Jan 12, 2024

This sequence change falls in intron 8 of the MSH6 gene. It does not directly change the encoded amino acid sequence of the MSH6 protein. This variant is present in population databases (no rsID available, gnomAD 0.006%). This variant has been observed in individuals with Lynch syndrome (PMID: 21520333, 31642931; Invitae; external communication). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 234703). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.31		Details are displayed if max score is > 0.2
DS_AL_spliceai		0.31		Position offset: 14

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs876661171; hg19: chr2-48033577;