7-5982965-A-G
Variant summary
Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PP3_Moderate
The NM_000535.7(PMS2):c.2033T>C(p.Ile678Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000102 in 1,568,066 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 Uncertain significance (★★).
Frequency
Consequence
NM_000535.7 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Uncertain_significance. Variant got 2 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.00000659 AC: 1AN: 151676Hom.: 0 Cov.: 31
GnomAD3 exomes AF: 0.0000102 AC: 2AN: 196332Hom.: 0 AF XY: 0.0000187 AC XY: 2AN XY: 107064
GnomAD4 exome AF: 0.0000106 AC: 15AN: 1416390Hom.: 0 Cov.: 26 AF XY: 0.0000171 AC XY: 12AN XY: 703286
GnomAD4 genome AF: 0.00000659 AC: 1AN: 151676Hom.: 0 Cov.: 31 AF XY: 0.0000135 AC XY: 1AN XY: 74084
ClinVar
Submissions by phenotype
not specified Uncertain:2
This variant is denoted PMS2 c.2033T>C at the cDNA level, p.Ile678Thr (I678T) at the protein level, and results in the change of an Isoleucine to a Threonine (ATC>ACC). This variant has not, to our knowledge, been published in the literature as being pathogenic or benign. PMS2 Ile678Thr was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. Since Isoleucine and Threonine differ in polarity, charge, size or other properties, this is considered a non-conservative amino acid substitution. PMS2 Ile678Thr occurs at a position where amino acids with properties similar to Isoleucine are tolerated across species and is located in the nuclease domain (Fukui 2011). In silico analyses are inconsistent regarding the effect this variant may have on protein structure and function. Based on currently available evidence, it is unclear whether PMS2 Ile678Thr is pathogenic or benign. We consider it to be a variant of uncertain significance. -
Variant summary: PMS2 c.2033T>C (p.Ile678Thr) results in a non-conservative amino acid change located in the MutL, C-terminal, dimerisation domain 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 1e-05 in 196332 control chromosomes, however the technology utilized for this dataset does not rule out pseudogene interference and thus cannot be relied upon to make any conclusions about variant significance for this gene. To our knowledge, no occurrence of c.2033T>C in individuals affected with Lynch Syndrome and no experimental evidence demonstrating its impact on protein function have been reported. Three 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. -
Hereditary nonpolyposis colorectal neoplasms Uncertain:1
This sequence change replaces isoleucine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 678 of the PMS2 protein (p.Ile678Thr). The frequency data for this variant in the population databases (gnomAD) is considered unreliable due to the presence of homologous sequence, such as pseudogenes or paralogs, in the genome. This missense change has been observed in individual(s) with pancreatic cancer (PMID: 37534630). ClinVar contains an entry for this variant (Variation ID: 142569). Invitae Evidence Modeling incorporating data from in vitro experimental studies (internal data) indicates that this missense variant is not expected to disrupt PMS2 function with a negative 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 cancer-predisposing syndrome Uncertain:1
The p.I678T variant (also known as c.2033T>C), located in coding exon 12 of the PMS2 gene, results from a T to C substitution at nucleotide position 2033. The isoleucine at codon 678 is replaced by threonine, an amino acid with similar properties. This amino acid position is well conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Based on the available evidence, the clinical significance of this variant remains unclear. -
Lynch syndrome 4 Uncertain:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at