chr2-47806651-G-A
Variant summary
Our verdict is Pathogenic. Variant got 16 ACMG points: 16P and 0B. PM2PM5PP3_StrongPP5_Very_Strong
The NM_000179.3(MSH6):c.4001G>A(p.Arg1334Gln) variant causes a missense, splice region change. The variant allele was found at a frequency of 0.00000275 in 1,455,180 control chromosomes in the GnomAD database, with no homozygous occurrence. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R1334P) has been classified as Pathogenic.
Frequency
Consequence
NM_000179.3 missense, splice_region
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Pathogenic. Variant got 16 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes Cov.: 32
GnomAD4 exome AF: 0.00000275 AC: 4AN: 1455180Hom.: 0 Cov.: 34 AF XY: 0.00000414 AC XY: 3AN XY: 724216
GnomAD4 genome Cov.: 32
ClinVar
Submissions by phenotype
not provided Pathogenic:7
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The MSH6 c.4001G>A (p.Arg1334Gln) variant has been reported in the published literature in affected individuals with colorectal cancer (PMIDs: 12373605 (2002), 15236168 (2004), 17453009 (2007), 21836479 (2011), 26681312 (2015), 30264118 (2018), 31447099 (2019), and 34178123 (2021)), breast cancer (PMIDs: 26681312 (2015) and 33471991)), endometrial cancer (PMIDs: 10508506 (1999) and 15236168 (2004), 33467402 (2021)), lung cancer (PMID: 31297337 (2019)), as well as in individuals diagnosed with Lynch Syndrome (PMIDs: 18566915 (2009), 20028993 (2010), and 27601186 (2016)). It was also found in a tumor as a somatic variant (PMID: 29887214 (2018)). Functional studies have demonstrated that this variant is damaging to protein function (PMIDs: 185669115 (2009), 28531214 (2017), and 30264118 (2018)). This variant has not been reported in large, multi-ethnic general populations (Genome Aggregation Database, http://gnomad.broadinstitute.org). Analysis of this variant using bioinformatics tools for the prediction of the effect of amino acid changes on protein structure and function yielded predictions that this variant is damaging. Based on the available information, this variant is classified as pathogenic. -
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PP1_strong, PP3, PP4, PP5, PM2_moderate, PS4_moderate -
Not observed in large population cohorts (gnomAD); In silico analysis supports a deleterious effect on splicing; In silico analysis supports that this missense variant does not alter protein structure/function; This variant is associated with the following publications: (PMID: 21081928, 23621914, 24362816, 18566915, 12547705, 15236168, 12373605, 20028993, 18415027, 27601186, 24705251, 26681312, 28502729, 24728189, 27768684, 17453009, 30283497, 29887214, 10508506, 8063241, 21836479, 31297337, 31447099, 32719484, 21120944, 17531815, 12019211, 34178123, 30787465) -
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Lynch syndrome Pathogenic:4
PVS1_MOD; PM2_SUP; PP4; PP1; PS3_SUP -
This variant causes a G>A nucleotide substitution at the last nucleotide of exon 9 of the MSH6 gene. Splice site prediction tools suggest that this variant may impact RNA splicing. A RT-PCR analysis of RNA derived from two carriers has reported out-of-frame skipping of exon 9 (UMD database, http://139.124.156.133/4D_molecules/UMD230309.html). This variant is expected to result in an absent or non-functional protein product. This variant has been reported in individuals affected with Lynch syndrome (PMID: 12547705, 17453009, 18566915, 27601186; UMD database) and in individuals affected with endometrial cancer (PMID: 33467402) and colorectal cancer (PMID: 26681312). Multifactorial likelihood model using health history, in silico, and experimental data has suggested this variant has a high probability of being pathogenic (InSiGHT database, http://insight-database.org/). This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). Loss of MSH6 function is a known mechanism of disease. Based on the available evidence, this variant is classified as Pathogenic. -
The p.Arg1334Gln variant in MSH6 has been reported in 4 individuals with MSH6-as sociated cancers and segregated with disease in 7 affected relatives from 2 fami lies (Hendriks 2004, Overbeek 2007, van Puijenbroek 2008, Klarskov 2011). It was absent from large population studies. This variant affects the last base of the exon, which is part of the 5? splice region and computational tools predict alt ered splicing, which is expected to lead to an altered or absent protein. Consis tent with this, tumors from patients harboring this variant showed absence of MS H6 protein (Hendriks 2004, Klarskov 2011). This variant was classified as Pathog enic on Sept 5, 2013 by the ClinGen-approved InSiGHT Expert Panel (ClinVar SCV00 0108190.2). In summary, this variant meets criteria to be classified as pathogen ic for Lynch syndrome. ACMG/AMP criteria applied: PP1_Str, PS4_Mod, PM2, PS3_Mod , PP3 (Richards 2015). -
Multifactorial likelihood analysis posterior probability >0.99 -
Lynch syndrome 5 Pathogenic:3
This variant is considered pathogenic. mRNA analysis has demonstrated abnormal mRNA splicing occurs [Myriad internal data]. This variant is strongly associated with more severe personal and family histories of cancer, typical for individuals with pathogenic variants in this gene [PMID: 25085752]. -
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Hereditary cancer-predisposing syndrome Pathogenic:2
The c.4001G>A pathogenic mutation (also known as p.R1334Q), located in coding exon 9 of the MSH6 gene, results from a G to A substitution at nucleotide position 4001. The amino acid change results in arginine to glutamine at codon 1334, an amino acid with highly similar 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. In silico splice site analysis predicts that this alteration will weaken the native splice donor site and RNA studies have demonstrated that this alteration results in abnormal splicing in the set of samples tested (Ambry internal data). This mutation has been reported in multiple Lynch syndrome patients as well as families and this variant segregated with disease in these families (Wijnen J et al. Nat Genet. 1999;23(2):142-144; Gille et al. Br J Cancer. 2002;87(8):892-897; Overbeek LI et al. Br J Cancer. 2007;96(10):1605-1612; Lagerstedt-Robinson K et al. Oncol. Rep. 2016 Nov;36(5):2823-2835). Functional studies have also demonstrated the pathogenicity of this variant (Houlleberghs H et al. PLoS Genet. 2017 May;13(5):e1006765). Based on the supporting evidence, this alteration is interpreted as a disease-causing mutation. -
This variant causes a G>A nucleotide substitution at the last nucleotide of exon 9 of the MSH6 gene. Splice site prediction tools suggest that this variant may impact RNA splicing. A RT-PCR analysis of RNA derived from two carriers has reported out-of-frame skipping of exon 9 (UMD database, http://139.124.156.133/4D_molecules/UMD230309.html). This variant is expected to result in an absent or non-functional protein product. This variant has been reported in individuals affected with Lynch syndrome (PMID: 12547705, 17453009, 18566915, 27601186; UMD database) and in individuals affected with endometrial cancer (PMID: 33467402) and colorectal cancer (PMID: 26681312). Multifactorial likelihood model using health history, in silico, and experimental data has suggested this variant has a high probability of being pathogenic (InSiGHT database, http://insight-database.org/). This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). Loss of MSH6 function is a known mechanism of disease. Based on the available evidence, this variant is classified as Pathogenic. -
Endometrial carcinoma Pathogenic:2
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The MSH6 p.Arg1334Gln variant was identified in 5 of 3358 proband chromosomes (frequency: 0.001) from Dutch, Danish and Norwegian individuals or families with HNPCC (Wijnen_1999_10508506, Nilbert_2009_18566915, Gille_2002_12373605 , Hendriks_2004_15236168, Overbeek_2007_17453009). A bioinformatics tool, CoDP (Combination of the Different Properties), that integrates the prediction results of three methods, namely MAPP, PolyPhen-2 and SIFT and two other structural properties, found the variant had no impact on the MSH6 protein (Terui_2013_23621914). The variant was also identified in dbSNP (ID: rs267608122) “With Likely pathogenic,Pathogenic allele”, ClinVar (classified as pathogenic, reviewed by an expert panel(2013); submitters: pathogenic by InSIGHT and Ambry Genetics, likely pathogenic by GeneDx and uncertain significance by Mayo Clinic Genetic Testing Laboratories), Clinvitae (4x), Cosmic (1x in a glioma), UMD-LSDB (4x as causal), Mismatch Repair Genes Variant Database, and Insight Hereditary Tumors Database (9x). The variant was not identified in GeneInsight-COGR, MutDB, Insight Colon Cancer Gene Variant Database, Zhejiang Colon Cancer Database, the 1000 Genomes Project, the NHLBI GO Exome Sequencing Project, the Exome Aggregation Consortium (August 8th 2016), or the Genome Aggregation Database (Feb 27, 2017). The p.Arg1334 residue is conserved in mammals and computational analyses (PolyPhen-2, SIFT, AlignGVGD, BLOSUM, MutationTaster) provide inconsistent predictions regarding the impact of the variant Gln to the protein; this information is not very predictive of pathogenicity. The p.Arg1334Gln variant occurs in the last nucleotide of the exon. This position has been shown to be part of the splicing consensus sequence and variants involving this position sometimes affect splicing. In addition, 4 of 5 in silico or computational prediction software programs (SpliceSiteFinder, MaxEntScan, NNSPLICE, GeneSplicer, HumanSpliceFinder) predict a greater than 10% difference in splicing. In summary, based on the above information the clinical significance of this variant cannot be determined with certainty at this time although we would lean towards a more pathogenic role for this variant. This variant is classified as likely pathogenic. -
Hereditary nonpolyposis colon cancer Pathogenic:1
Variant summary: MSH6 c.4001G>A (p.Arg1334Gln) results in a conservative amino acid change in the encoded protein sequence. Three of five in-silico tools predict a damaging effect of the variant on protein function. Computational tools predict a significant impact on normal splicing: Two predict the variant abolishes a canonical 5' splicing donor site. One predicts the variant weakens this site. The variant was absent in 244224 control chromosomes (gnomAD). c.4001G>A has been reported in the literature in multiple individuals affected with Lynch Syndrome (e.g. Wjnen_1999, Susswein_2016, Sun_2019, Yang_2021). These data indicate that the variant is very likely to be associated with disease. The following publications have been ascertained in the context of this evaluation (PMID: 26681312, 31297337, 34178123, 10508506). ClinVar contains an entry for this variant (Variation ID: 89506). Based on the evidence outlined above, the variant was classified as pathogenic. -
Hereditary nonpolyposis colorectal neoplasms Pathogenic:1
This sequence change replaces arginine, which is basic and polar, with glutamine, which is neutral and polar, at codon 1334 of the MSH6 protein (p.Arg1334Gln). 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 individual(s) with clinical features of Lynch syndrome (PMID: 10508506, 15236168, 17453009, 21081928, 21836479, 26681312). It has also been observed to segregate with disease in related individuals. Invitae Evidence Modeling of clinical and family history, age, sex, and reported ancestry of multiple individuals with this MSH6 variant has been performed. This variant is expected to be pathogenic with a positive predictive value of at least 99%. This is a validated machine learning model that incorporates the clinical features of 1,370,736 individuals referred to our laboratory for MSH6 testing. ClinVar contains an entry for this variant (Variation ID: 89506). An algorithm developed specifically for the MSH6 gene suggests that this missense change is likely to be tolerated (PMID: 23621914). 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 (internal data). However the mRNA is not expected to undergo nonsense-mediated decay. For these reasons, this variant has been classified as Pathogenic. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at