rs63751083
Variant summary
Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM5
The NM_000249.4(MLH1):c.1421G>A(p.Arg474Gln) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000958 in 1,461,872 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R474G) has been classified as Likely benign.
Frequency
Consequence
NM_000249.4 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 Cov.: 32
GnomAD3 exomes AF: 0.00000795 AC: 2AN: 251418Hom.: 0 AF XY: 0.00 AC XY: 0AN XY: 135874
GnomAD4 exome AF: 0.00000958 AC: 14AN: 1461872Hom.: 0 Cov.: 32 AF XY: 0.00000825 AC XY: 6AN XY: 727238
GnomAD4 genome Cov.: 32
ClinVar
Submissions by phenotype
Colorectal cancer, hereditary nonpolyposis, type 2 Uncertain:3
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This variant is classified as a variant of uncertain significance as there is insufficient evidence to determine its impact on protein function and/or cancer risk. -
not provided Uncertain:2
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In the published literature, this variant has been reported in individuals with Lynch syndrome (PMID: 18561205 (2008), 30256826 (2018)), colon cancer (PMID: 23741719 (2013)), and breast cancer (PMID: 33471991 (2021), see also LOVD (https://databases.lovd.nl/shared/variants/MLH1)). Functional studies have reported this variant does not have a damaging effect on protein function (PMID: 17510385 (2007), 18561205 (2008), 30998989 (2019)). The frequency of this variant in the general population, 0.000008 (2/251418 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:1Benign:1
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The p.R474Q variant (also known as c.1421G>A), located in coding exon 13 of the MLH1 gene, results from a G to A substitution at nucleotide position 1421. The arginine at codon 474 is replaced by glutamine, an amino acid with highly similar properties. This variant has been identified in a proband who met Amsterdam II criteria for Lynch syndrome (Martin-Morales L et al. PLoS One, 2018 Sep;13:e0203885). In addition, this alteration has been reported in an individual either fulfilling Amsterdam II criteria or having a tumor demonstrating microsatellite instability (Tournier I et al. Hum Mutat, 2008 Dec;29:1412-24). This alteration was detected in a patient with colon cancer who had at least two family members with colorectal and/or endometrial cancer in two generations (Stojcev Z et al. Acta Biochim Pol, 2013 Jun;60:195-8). However, in multiple assays testing MLH1 function, this variant showed functionally normal results (Takahashi M et al. Cancer Res, 2007 May;67:4595-604; Borràs E et al. Hum Mutat, 2012 Nov;33:1576-88; Bouvet D et al. Gastroenterology, 2019 Aug;157:421-431; Rath A et al. Hum Mutat, 2022 Dec;43:2295-2307). 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. -
not specified Uncertain:1
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Lynch syndrome Benign:1
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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