chr3-37014436-C-A
Variant summary
Our verdict is Likely benign. Variant got -1 ACMG points: 0P and 1B. BP6
The NM_001167618.3(MLH1):c.-42C>A 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 0.0000542 in 1,548,896 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).
Frequency
Consequence
NM_001167618.3 5_prime_UTR_premature_start_codon_gain
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Likely_benign. Variant got -1 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000131 AC: 2AN: 152106Hom.: 0 Cov.: 32
GnomAD3 exomes AF: 0.0000239 AC: 6AN: 250778Hom.: 0 AF XY: 0.0000295 AC XY: 4AN XY: 135596
GnomAD4 exome AF: 0.0000587 AC: 82AN: 1396790Hom.: 0 Cov.: 25 AF XY: 0.0000601 AC XY: 42AN XY: 699082
GnomAD4 genome AF: 0.0000131 AC: 2AN: 152106Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1AN XY: 74292
ClinVar
Submissions by phenotype
not provided Uncertain:4
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In silico analysis indicates that this missense variant does not alter protein structure/function; This variant is associated with the following publications: (PMID: 23338612, 33471991, 22753075, 34359559, 29641532) -
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Variant summary: MLH1 c.682C>A affects a non-conserved nucleotide and results in a replacement of a Leucine (L) with a Methionine (M). Both residues are medium size and hydrophobic, therefore this Leucine to Methionine substitution does not alter the physico-chemical properties of the protein. 3/4 in silico tools predict the variant to be disease causing. It was observed in the large and broad cohorts of the ExAC project at an allele frequency of 0.0026% which does not exceed the maximal allele frequency of a disease causing MLH1 allele (0.07%) to exclude pathogenicity. To our knowledge, the variant has not been reported in affected patients from the literature and in vitro/vivo studies to assess the functional impact of the variant have not been published either. Clinical diagnostic centers classify variant as Uncertain via ClinVar (without evidence to independently evaluate). Due to the lack of clinical and functional data, the variant was classified as a variant of uncertain significance until more information becomes available. -
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]. -
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Hereditary cancer-predisposing syndrome Uncertain:2Benign:1
This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -
This missense variant replaces leucine with methionine at codon 228 of the MLH1 protein. Computational prediction is inconclusive regarding the impact of this variant on protein structure and function (internally defined REVEL score threshold 0.5 < inconclusive < 0.7, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. In a large breast cancer case-control study, this variant has been reported in 9/60466 cases and 1/53461 unaffected controls (PMID: 33471991). This variant has been identified in 7/282172 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. -
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not specified Uncertain:1
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Lynch syndrome Uncertain:1
This missense variant replaces leucine with methionine at codon 228 of the MLH1 protein. Computational prediction is inconclusive regarding the impact of this variant on protein structure and function (internally defined REVEL score threshold 0.5 < inconclusive < 0.7, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. In a large breast cancer case-control study, this variant has been reported in 9/60466 cases and 1/53461 unaffected controls (PMID: 33471991). This variant has been observed in an individual with a personal or family history of breast or ovarian cancer (PMID: 34359559). This variant has been identified in 7/282172 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. -
MLH1-related disorder Uncertain:1
The MLH1 c.682C>A variant is predicted to result in the amino acid substitution p.Leu228Met. This variant has been reported in and individual with a personal and/or family history of hereditary breast and ovarian cancer (Table S3, Lesueur et al. 2021. PubMed ID: 34359559). It has also been reported in a control individual from a melanoma cohort study (Supplement, Pritchard et al. 2018. PubMed ID: 29641532). This variant is reported in 0.0054% of alleles in individuals of European (Non-Finnish) descent in gnomAD and has conflicting interpretations regarding its pathogenicity in ClinVar, ranging from likely benign to uncertain (https://www.ncbi.nlm.nih.gov/clinvar/variation/184050/). At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -
Hereditary nonpolyposis colorectal neoplasms Uncertain:1
This sequence change replaces leucine, which is neutral and non-polar, with methionine, which is neutral and non-polar, at codon 228 of the MLH1 protein (p.Leu228Met). This variant is present in population databases (rs751628735, gnomAD 0.006%). This variant has not been reported in the literature in individuals affected with MLH1-related conditions. ClinVar contains an entry for this variant (Variation ID: 184050). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is not expected to disrupt MLH1 protein function with a negative predictive value of 95%. RNA analysis performed to evaluate the impact of this missense change on mRNA splicing indicates it does not significantly alter splicing (internal data). 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