rs754554026
Variant summary
Our verdict is Likely benign. Variant got -2 ACMG points: 0P and 2B. BP4_Moderate
The NM_000249.4(MLH1):c.1490G>A(p.Arg497Gln) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000217 in 1,614,036 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).
Frequency
Consequence
NM_000249.4 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Likely_benign. Variant got -2 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.00000657 AC: 1AN: 152170Hom.: 0 Cov.: 32
GnomAD3 exomes AF: 0.0000278 AC: 7AN: 251480Hom.: 0 AF XY: 0.0000221 AC XY: 3AN XY: 135908
GnomAD4 exome AF: 0.0000233 AC: 34AN: 1461866Hom.: 0 Cov.: 32 AF XY: 0.0000220 AC XY: 16AN XY: 727242
GnomAD4 genome AF: 0.00000657 AC: 1AN: 152170Hom.: 0 Cov.: 32 AF XY: 0.0000134 AC XY: 1AN XY: 74356
ClinVar
Submissions by phenotype
not provided Uncertain:2
In silico analysis, which includes protein predictors and evolutionary conservation, supports a deleterious effect; Has not been previously published as a germline pathogenic or benign variant to our knowledge; This variant is associated with the following publications: (PMID: 29596542, 22608206) -
The MLH1 c.1490G>A (p.Arg497Gln) variant has been reported in the published literature in an individual with colorectal cancer (PMID: 32658311 (2021)), and an individual referred for hereditary cancer testing (PMID: 34359559 (2021)). The frequency of this variant in the general population, 0.00013 (4/30616 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 predictions that this variant is benign. Based on the available information, we are unable to determine the clinical significance of this variant. -
Hereditary cancer-predisposing syndrome Uncertain:2
This missense variant replaces arginine with glutamine at codon 497 of the MLH1 protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has not been reported in individuals affected with MLH1-related disorders in the literature. This variant has been identified in 7/251480 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 p.R497Q variant (also known as c.1490G>A), located in coding exon 13 of the MLH1 gene, results from a G to A substitution at nucleotide position 1490. The arginine at codon 497 is replaced by glutamine, an amino acid with highly similar properties. This alteration was seen in 0/732 breast cancer patients, 1/189 colorectal cancer patients and 0/490 cancer-free elderly controls in a Turkish population (Akcay IM et al. Int J Cancer, 2021 Jan;148:285-295). This amino acid position is well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Based on the available evidence, the clinical significance of this alteration remains unclear. -
Colorectal cancer, hereditary nonpolyposis, type 2 Uncertain:1Benign:1
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This variant is considered likely benign. This variant is strongly associated with less severe personal and family histories of cancer, typical for individuals without pathogenic variants in this gene [PMID: 27363726]. -
not specified Uncertain:1
Variant summary: MLH1 c.1490G>A (p.Arg497Gln) results in a conservative amino acid change in the encoded protein sequence. Five of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 2.8e-05 in 251480 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. To our knowledge, no occurrence of c.1490G>A in individuals affected with Hereditary Nonpolyposis Colorectal Cancer/Lynch syndrome and no experimental evidence demonstrating its impact on protein function have been reported. Four submitters have cited clinical-significance assessments for this variant to ClinVar after 2014 (VUS, n=4; LB, n=1). Based on the evidence outlined above, the variant was classified as uncertain significance. -
Lynch syndrome Uncertain:1
This missense variant replaces arginine with glutamine at codon 497 of the MLH1 protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). 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 an individual suspected of having hereditary breast/ovarian cancer (PMID: 34359559). This variant has been identified in 7/251480 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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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at