chr3-37040191-C-T
Variant summary
Our verdict is Likely benign. Variant got -1 ACMG points: 0P and 1B. BP6
The NM_000249.4(MLH1):c.1564C>T(p.Arg522Trp) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000192 in 1,612,972 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. R522Q) has been classified as Likely benign.
Frequency
Consequence
NM_000249.4 missense
Scores
Clinical Significance
Conservation
Genome browser will be placed here
ACMG classification
Verdict is Likely_benign. Variant got -1 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000197 AC: 3AN: 151966Hom.: 0 Cov.: 32
GnomAD3 exomes AF: 0.0000159 AC: 4AN: 251108Hom.: 0 AF XY: 0.0000221 AC XY: 3AN XY: 135698
GnomAD4 exome AF: 0.0000192 AC: 28AN: 1461006Hom.: 0 Cov.: 30 AF XY: 0.0000261 AC XY: 19AN XY: 726884
GnomAD4 genome AF: 0.0000197 AC: 3AN: 151966Hom.: 0 Cov.: 32 AF XY: 0.0000270 AC XY: 2AN XY: 74200
ClinVar
Submissions by phenotype
not provided Uncertain:4
- -
Variant summary: The MLH1 c.1564C>T (p.Arg522Trp) variant involves the alteration of a conserved nucleotide. 3/4 in silico tools predict a damaging outcome (SNPs&GO not captured due to low reliability index). This variant was found in 4/121218 control chromosomes at a frequency of 0.000033, which does not exceed the estimated maximal expected allele frequency of a pathogenic MLH1 variant (0.0007105). In addition, multiple clinical diagnostic laboratories classified this variant as VUS, without evidence to independently evaluate. This variant, to our knowledge, has not been reported as a germ-line variant in affected individuals. One study showed this variant with protein expression level not significantly different from WT (Hinrichsen_2013). Because of the absence of clinical information and the lack of functional studies, the variant was classified as a variant of uncertain significance (VUS) until additional information becomes available. -
- -
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 an individual with personal/family history suspicious for Lynch syndrome (Lagerstedt-Robinson et al., 2016); Published functional studies are inconclusive: slightly reduced protein expression but mismatch repair activity comparable to wild-type (Hinrichsen et al., 2013); This variant is associated with the following publications: (PMID: 26976419, 14688830, 24362816, 22753075, 12799449, 20533529, 23403630, 27601186) -
Colorectal cancer, hereditary nonpolyposis, type 2 Uncertain:2Benign:1
- -
- -
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]. -
Hereditary cancer-predisposing syndrome Uncertain:2
The p.R522W variant (also known as c.1564C>T), located in coding exon 14 of the MLH1 gene, results from a C to T substitution at nucleotide position 1564. The arginine at codon 522 is replaced by tryptophan, an amino acid with dissimilar properties. This variant was reported in a Swedish family suspected to have Lynch syndrome, but no clinical or family history information was provided (Lagerstedt-Robinson K et al. Oncol. Rep. 2016 Nov;36(5):2823-2835). In another study, the p.R522W alteration was detected as a somatic alteration in a Dukes' B2 colon cancer that exhibited microsatellite stability (Kámory E et al. Pathol. Oncol. Res. 2003;9(4): 236-41). Functional analyses of this alteration using quantitative PCR, pulse-chase and thermal stability indicate that p.R522W does not have a significant decrease in expression or MMR proficiency compared to wild-type (Hinrichsen I et al. Clin. Cancer Res. 2013 May;19(9):2432-41). This amino acid position is not well 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 arginine with tryptophan at codon 522 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). An experimental functional study has shown this variant had normal mismatch repair activity and only a moderate impact on MLH1 expression (PMID: 23403630). This variant has been reported in an individual suspected of having Lynch syndrome (PMID: 27601186). This variant has been identified in 5/282468 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. -
Lynch syndrome Uncertain:1
This missense variant replaces arginine with tryptophan at codon 522 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. An experimental functional study has shown this variant had normal mismatch repair activity and only a moderate impact on MLH1 expression (PMID: 23403630). This variant has been reported in an individual suspected of having Lynch syndrome in the literature (PMID: 27601186). This variant has been identified in 5/282468 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
- -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at