rs1553333420
Variant summary
Our verdict is Uncertain significance. Variant got 1 ACMG points: 1P and 0B. PM4_Supporting
The NM_001406800.1(MSH6):c.3835_3837dupTTA(p.Leu1279dup) variant causes a conservative inframe insertion change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000013 in 1,613,884 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).
Frequency
Consequence
NM_001406800.1 conservative_inframe_insertion
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Uncertain_significance. Variant got 1 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000197 AC: 3AN: 152100Hom.: 0 Cov.: 32
GnomAD3 exomes AF: 0.0000239 AC: 6AN: 250878Hom.: 0 AF XY: 0.0000295 AC XY: 4AN XY: 135702
GnomAD4 exome AF: 0.0000123 AC: 18AN: 1461784Hom.: 0 Cov.: 35 AF XY: 0.0000138 AC XY: 10AN XY: 727192
GnomAD4 genome AF: 0.0000197 AC: 3AN: 152100Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0AN XY: 74278
ClinVar
Submissions by phenotype
not specified Uncertain:2
Variant summary: MSH6 c.3848_3850dupTTA (p.Ile1283dup) results in an in-frame duplication with the insertion of one amino acid into the C-terminal domain of the MSH6 protein (IPR000432). The variant allele was found at a frequency of 2.5e-05 in 282272 control chromosomes, predominantly found in the European subpopulation with an allele frequency of 5.4e-05 in the gnomAD database. However, the variant was found at an even higher frequency in the Swedish (5/26108 alleles; allele frequency of ~0.0002); and this frequency is higher than the maximum expected for a pathogenic variant in MSH6 causing Lynch Syndrome phenotype (0.00014), suggesting a benign role for the variant. The variant, c.3848_3850dupTTA, has been reported in the literature in Scandinavian individuals affected with colon cancer and suspected Lynch syndrome (Hansen_2014, Lagerstedt-Robinson_2016, Haraldsdottir_2017), but was also reported to be found with similar allele frequencies among healthy Icelandic controls (Haraldsdottir_2017). These reports do not provide unequivocal conclusions about association of the variant with Lynch Syndrome. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Four clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -
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not provided Uncertain:2
The MSH6 c.3848_3850dup (p.Ile1283dup) variant has been reported in the published literature in individuals/families with Lynch syndrome (PMID: 27601186 (2016)). It was also reported in 3 Icelandic individuals with colorectal cancer, and observed in similar frequency in healthy controls in a case-control study (PMID: 28466842 (2017)). The frequency of this variant in the general population, 0.000054 (7/128874 chromosomes (Genome Aggregation Database, http://gnomad.broadinstitute.org)), is uninformative in the assessment of its pathogenicity. Based on the available information, we are unable to determine the clinical significance of this variant. -
In-frame duplication of 1 amino acid in a non-repeat region; Observed in at least two individuals suspected of having Lynch syndrome, and was identified at similar frequencies between Icelandic colorectal cancer patients and controls (p=0.69) (Lagerstedt-Robinson et al., 2016; Haraldsdottir et al., 2017); This variant is associated with the following publications: (PMID: 24689082, 28466842, 17531815, 21120944, 27601186) -
Hereditary cancer-predisposing syndrome Uncertain:2
This variant causes an in-frame duplication of one amino acid of the MSH6 protein. Splice site prediction tools suggest that this variant may not impact RNA splicing. To our knowledge, functional studies have not been performed for this variant. This variant has been reported in individuals affected with Lynch syndrome-associated disease or suspected of Lynch syndrome (PMID: 24689082, 27601186, 28466842). However, several individuals affected with colorectal cancer had tumors that displayed intact protein via immunohistochemistry analysis and the variant has also been identified in healthy controls, with no significant association with colorectal cancer found in the study population (PMID: 28466842). This variant has been identified in 7/282272 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. -
The c.3848_3850dupTTA variant (also known as p.I1283dup), located in coding exon 9 of the MSH6 gene, results from an in-frame duplication of TTA at nucleotide positions 3848 to 3850. This results in the duplication of an extra isoleucine residue at codon 1283. This alteration has been reported in multiple individuals with personal and/or family history consistent with Lynch syndrome (Lagerstedt-Robinson K et al. Oncol. Rep., 2016 Nov;36:2823-2835; Haraldsdottir S et al. Nat Commun, 2017 05;8:14755). However, this variant has been identified in multiple probands whose Lynch syndrome-associated tumors demonstrated normal mismatch repair protein expression by immunohistochemistry (IHC) (Ambry internal data; Haraldsdottir S et al. Nat Commun, 2017 05;8:14755). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis (Choi Y et al. PLoS ONE. 2012; 7(10):e46688). Based on the available evidence, the clinical significance of this variant remains unclear. -
Lynch syndrome Uncertain:1
This variant causes an in-frame duplication of one amino acid of the MSH6 protein. Splice site prediction tools suggest that this variant may not impact RNA splicing. To our knowledge, functional studies have not been performed for this variant. This variant has been reported in individuals affected with Lynch syndrome-associated disease or suspected of Lynch syndrome (PMID: 24689082, 27601186, 28466842). However, several individuals affected with colorectal cancer had tumors that displayed intact protein via immunohistochemistry analysis and the variant has also been identified in healthy controls, with no significant association with colorectal cancer found in the study population (PMID: 28466842). This variant has been identified in 7/282272 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. -
Hereditary nonpolyposis colorectal neoplasms Benign:1
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Lynch syndrome 5 Other:1
Variant interpreted as Uncertain significance and reported on 05-02-2019 by Lab Invitae. GenomeConnect-Invitae Patient Insights Network assertions are reported exactly as they appear on the patient-provided report from the testing laboratory. Registry team members make no attempt to reinterpret the clinical significance of the variant. Phenotypic details are available under supporting information. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at