3-36996706-C-G
Variant summary
Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2PP3_Strong
The NM_001167617.3(MLH1):c.-86C>G variant causes a 5 prime UTR premature start codon gain change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000274 in 1,458,640 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_001167617.3 5_prime_UTR_premature_start_codon_gain
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Likely_pathogenic. Variant got 6 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes Cov.: 32
GnomAD3 exomes AF: 0.00000398 AC: 1AN: 251396Hom.: 0 AF XY: 0.00000736 AC XY: 1AN XY: 135872
GnomAD4 exome AF: 0.00000274 AC: 4AN: 1458640Hom.: 0 Cov.: 30 AF XY: 0.00000551 AC XY: 4AN XY: 725930
GnomAD4 genome Cov.: 32
ClinVar
Submissions by phenotype
Lynch syndrome Uncertain:2
This missense variant replaces isoleucine with methionine at codon 68 of the MLH1 protein. Computational prediction suggests that this variant may have deleterious impact on protein structure and function (internally defined REVEL score threshold >= 0.7, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in an individual affected with colorectal cancer but without the clinical features of Lynch syndrome (PMID: 25435955). This variant has been identified in 1/251396 chromosomes in the general population by the Genome Aggregation Database (gnomAD). Different variants affecting the same codon, c.203T>G (p.Ile68Ser) and c.203T>A (p.Ile68Asn), are considered to be disease-causing (ClinVar variation ID: 820585, 90008), suggesting that this position is important for the protein function. 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. -
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not provided Uncertain:2
Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Observed in individuals with colorectal cancer (Vodicka et al., 2015); This variant is associated with the following publications: (PMID: 25576899, 22753075, 16083711, 21120944, 25435955) -
The MLH1 c.204C>G (p.Ile68Met) variant has been reported in the published literature in individuals with rectal cancer (PMID: 25435955 (2015)) and thyroid cancer (PMID: 25576899 (2015)). At least one other missense variant at this codon (MLH1 c.203T>A (p.Ile68Asn), Quest internal data, ClinVar Variation ID: 90008) is considered to be pathogenic or likely pathogenic, suggesting this variant may also cause disease. The frequency of this variant in the general population, 0.000004 (1/251396 chromosomes (Genome Aggregation Database, http://gnomad.broadinstitute.org)), is uninformative in the assessment of its pathogenicity. Analysis of this variant using bioinformatics tools for the prediction of the effect of amino acid changes on protein structure and function yielded conflicting predictions that this variant is benign or damaging. Based on the available information, we are unable to determine the clinical significance of this variant. -
Hereditary cancer-predisposing syndrome Uncertain:2
The p.I68M variant (also known as c.204C>G), located in coding exon 2 of the MLH1 gene, results from a C to G substitution at nucleotide position 204. The isoleucine at codon 68 is replaced by methionine, an amino acid with highly similar properties. This alteration has been reported in both germline and tumor DNA of a 59 year old female with rectal cancer; however, the expression of MLH1 was not altered in the tumor. Authors also report that the amino acid residue 68 is located within the enzymatic core on the MLH1 protein which interacts with ATP; they conclude that a substitution by methionine may decrease MLH1 activity (Vodicka P et al, Oncol Lett 2015 Jan; 9(1):183-186). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -
This missense variant replaces isoleucine with methionine at codon 68 of the MLH1 protein. Computational prediction suggests that this variant may have deleterious impact on protein structure and function (internally defined REVEL score threshold >= 0.7, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in an individual affected with colorectal cancer but without the clinical features of Lynch syndrome (PMID: 25435955). This variant has been identified in 1/251396 chromosomes in the general population by the Genome Aggregation Database (gnomAD). Different variants affecting the same codon, c.203T>G (p.Ile68Ser) and c.203T>A (p.Ile68Asn), are considered to be disease-causing (ClinVar variation ID: 820585, 90008), suggesting that this position is important for the protein function. 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. -
Colorectal cancer, hereditary nonpolyposis, type 2 Uncertain:1
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Hereditary nonpolyposis colorectal neoplasms Uncertain:1
This sequence change replaces isoleucine, which is neutral and non-polar, with methionine, which is neutral and non-polar, at codon 68 of the MLH1 protein (p.Ile68Met). This variant is present in population databases (rs780141938, gnomAD 0.0009%). This missense change has been observed in individual(s) with colorectal cancer (PMID: 25435955). ClinVar contains an entry for this variant (Variation ID: 486852). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on MLH1 protein function. This variant disrupts the p.Ile68 amino acid residue in MLH1. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 10082584, 11304573, 11555625, 12810663, 14961575, 17510385, 24362816). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. 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. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at