3-37040260-A-G

Position:

chr3-37040260-A-G

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 1P and 0B. PP3

The NM_000249.4(MLH1):c.1633A>G(p.Thr545Ala) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000601 in 1,613,798 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

Genomes: 𝑓 0.000033 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000063 ( 0 hom. )

Consequence

MLH1
NM_000249.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:18B:1

Conservation

PhyloP100: 9.08

Variant links:

Genes affected

MLH1 (HGNC:7127): (mutL homolog 1) The protein encoded by this gene can heterodimerize with mismatch repair endonuclease PMS2 to form MutL alpha, part of the DNA mismatch repair system. When MutL alpha is bound by MutS beta and some accessory proteins, the PMS2 subunit of MutL alpha introduces a single-strand break near DNA mismatches, providing an entry point for exonuclease degradation. The encoded protein is also involved in DNA damage signaling and can heterodimerize with DNA mismatch repair protein MLH3 to form MutL gamma, which is involved in meiosis. This gene was identified as a locus frequently mutated in hereditary nonpolyposis colon cancer (HNPCC). [provided by RefSeq, Aug 2017]

MLH1 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 1 ACMG points.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.821

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MLH1	NM_000249.4 link	c.1633A>G	p.Thr545Ala	missense_variant	14/19	ENST00000231790.8	NP_000240.1	P40692-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MLH1	ENST00000231790.8 link	c.1633A>G	p.Thr545Ala	missense_variant	14/19	1	NM_000249.4	ENSP00000231790.3		P40692-1

Frequencies

GnomAD3 genomes

AF:

0.0000329

AC:

AN:

152106

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000735

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000398

AC:

AN:

251320

Hom.:

AF XY:

0.0000294

AC XY:

AN XY:

135834

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000880

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000629

AC:

AN:

1461692

Hom.:

Cov.:

AF XY:

0.0000550

AC XY:

AN XY:

727160

show subpopulations

Gnomad4 AFR exome

AF:

0.0000598

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000782

Gnomad4 OTH exome

AF:

0.0000497

GnomAD4 genome

AF:

0.0000329

AC:

AN:

152106

Hom.:

Cov.:

AF XY:

0.0000404

AC XY:

AN XY:

74316

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000735

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000773

Hom.:

Bravo

AF:

0.0000151

ExAC

AF:

0.0000494

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:18Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:6

Uncertain significance, no assertion criteria provided	clinical testing	Laboratory of Diagnostic Genome Analysis, Leiden University Medical Center (LUMC)	-	- -
Uncertain significance, no assertion criteria provided	clinical testing	Clinical Genetics, Academic Medical Center	-	- -
Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Apr 10, 2023	Published functional studies demonstrate splicing comparable to wild-type in a minigene assay and in patient RNA analysis, but the impact that this variant has on protein function was not evaluated (van der Klift et al., 2015); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 21404117, 18566915, 26898890, 28259476, 12799449, 20533529, 22753075, 26247049) -
Uncertain significance, criteria provided, single submitter	clinical testing	Quest Diagnostics Nichols Institute San Juan Capistrano	Sep 20, 2024	The MLH1 c.1633A>G (p.Thr545Ala) variant has been reported in the published literature in suspected Lynch Syndrome families and in an individual who met Amsterdam II criteria for Lynch Syndrome but also carried a pathogenic MSH2 variant (PMIDs: 18566915 (2009), 21404117 (2011), and 26247049 (2015)). It has also been reported in individuals with breast and/or ovarian cancer (PMID: 26898890 (2016), 35884425 (2022)) as well as in reportedly healthy individuals (PMID: 35884425 (2022)). An experimental study using a minigene assay and patient RNA analysis reported that this variant does not affect MLH1 splicing, however the effect on MLH1 protein activity was not assessed (PMID: 26247049 (2015)). The frequency of this variant in the general population, 0.000085 (11/129046 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 damaging. Based on the available information, we are unable to determine the clinical significance of this variant. -
Uncertain significance, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Aug 01, 2022	MLH1: PM2, BP5 -
Uncertain significance, no assertion criteria provided	clinical testing	Clinical Genetics Laboratory, Department of Pathology, Netherlands Cancer Institute	-	- -

not specified

Uncertain:3

Uncertain significance, criteria provided, single submitter	clinical testing	Center for Genomic Medicine, Rigshospitalet, Copenhagen University Hospital	Mar 04, 2025	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Feb 22, 2024	Variant summary: MLH1 c.1633A>G (p.Thr545Ala) results in a non-conservative amino acid change located in the DNA mismatch repair protein Mlh1, C-terminal domain (IPR032189) of the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 4e-05 in 251320 control chromosomes. This frequency is not significantly higher than estimated for a pathogenic variant in MLH1 causing Hereditary Nonpolyposis Colorectal Cancer (4e-05 vs 0.00071), allowing no conclusion about variant significance. c.1633A>G has been reported in the literature in individuals affected with cancer (e.g. Nilbert_2009, Hardt_2011, Caminsky_2016) without strong evidence for causality. These reports do not provide unequivocal conclusions about association of the variant with Lynch Syndrome. A co-occurrence with a pathogenic variant in MSH2 was reported by Hardt_2011 (variant not specified), providing supporting evidence for a benign role. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publications have been ascertained in the context of this evaluation (PMID: 18566915, 21404117, 26247049, 26898890). ClinVar contains an entry for this variant (Variation ID: 89812). Based on the evidence outlined above, the variant was classified as VUS-possibly benign. -
Uncertain significance, no assertion criteria provided	clinical testing	Mayo Clinic Laboratories, Mayo Clinic	-	- -

Colorectal cancer, hereditary nonpolyposis, type 2

Uncertain:3

Uncertain significance, no assertion criteria provided	clinical testing	Diagnostic Laboratory, Department of Genetics, University Medical Center Groningen	-	- -
Uncertain significance, criteria provided, single submitter	clinical testing	St. Jude Molecular Pathology, St. Jude Children's Research Hospital	Oct 28, 2021	The MLH1 c.1633A>G (p.Thr545Ala) missense change has a maximum subpopulation frequency of 0.0085% in gnomAD v2.1.1 (https://gnomad.broadinstitute.org/variant/3-37081751-A-G). Six of seven in silico tools predict a deleterious effect of this variant on protein function (PP3), but to our knowledge these predictions have not been confirmed by functional assays. This variant has also been observed in an individual with Lynch syndrome who also harbored a pathogenic variant in MSH2 (BP5; PMID: 21404117). It has also been reported in 1/1358 non-cancer control individuals in a study of individuals with multiple primary cancers (PMID: 29641532). In summary, this variant meets criteria to be classified as of uncertain significance based on the ACMG/AMP criteria: PP3, BP5. -
Uncertain significance, criteria provided, single submitter	clinical testing	Baylor Genetics	Jan 24, 2024	- -

Hereditary cancer-predisposing syndrome

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Nov 20, 2024	The p.T545A variant (also known as c.1633A>G), located in coding exon 14 of the MLH1 gene, results from an A to G substitution at nucleotide position 1633. The threonine at codon 545 is replaced by alanine, an amino acid with similar properties. This variant was reported in conjunction with a pathogenic mutation in MSH2 in an individual diagnosed with breast and colon cancer whose family met Amsterdam I criteria (Hardt K et al. Fam Cancer. 2011 Jun;10:273-84). This amino acid position is highly 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. -
Uncertain significance, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Feb 14, 2023	This missense variant replaces threonine with alanine at codon 545 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 two suspected Lynch syndrome families (PMID: 18566915, 26247049) and one diagnosed Lynch syndrome family (Amsterdam II criteria) that has three colon cancer affected members, one of whom also has a pathogenic MSH2 covariant (PMID: 21404117). This variant has also been observed in an individual affected with familial breast cancer (PMID: 26898890). This variant has been identified in 11/282688 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. -

Breast and/or ovarian cancer

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario

Apr 25, 2023

- -

Muir-Torré syndrome;C1333991:Colorectal cancer, hereditary nonpolyposis, type 2;C5399763:Mismatch repair cancer syndrome 1

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Mar 17, 2024

- -

Lynch syndrome

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

All of Us Research Program, National Institutes of Health

Jul 29, 2024

This missense variant replaces threonine with alanine at codon 545 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). Splice site prediction tools suggest that this variant may not impact RNA splicing. To our knowledge, functional studies have not been reported for this variant. This variant has been reported in two suspected Lynch syndrome families (PMID: 18566915, 26247049) and one diagnosed Lynch syndrome family (Amsterdam II criteria) that has three colon cancer affected members, one of whom also has a pathogenic MSH2 covariant (PMID: 21404117). This variant also has been observed in an individual affected with familial breast cancer (PMID: 26898890). This variant has been identified in 11/282688 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

Uncertain significance, no assertion criteria provided

clinical testing

PreventionGenetics, part of Exact Sciences

Jan 17, 2024

The MLH1 c.1633A>G variant is predicted to result in the amino acid substitution p.Thr545Ala. This variant has been reported as a variant of uncertain significance in an individual with Lynch syndrome (Nilbert et al. 2009. PubMed ID: 18566915) and in an individual with Lynch syndrome that harbored a pathogenic variant in MSH2 (Hardt et al. 2011. PubMed ID: 21404117, Table S1). Results from a minigene study indicates this variant does not impact splicing (Tables 1 and 2, van der Klift et al. 2015. PubMed ID: 26247049). This variant is reported in 0.0085% of alleles in individuals of European (Non-Finnish) descent in gnomAD. It is interpreted as uncertain in ClinVar (https://www.ncbi.nlm.nih.gov/clinvar/variation/89812/). 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

Benign:1

Benign, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 05, 2025

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.57

BayesDel_addAF

Pathogenic

0.35

BayesDel_noAF

Pathogenic

0.46

CADD

Uncertain

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.91

D;.;.;.;.;.;D

Eigen

Pathogenic

0.70

Eigen_PC

Uncertain

0.62

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.96

D;D;.;.;.;D;D

M_CAP

Pathogenic

0.51

MetaRNN

Pathogenic

0.82

D;D;D;D;D;D;D

MetaSVM

Pathogenic

1.0

MutationAssessor

Pathogenic

3.5

M;.;.;.;.;.;.

PrimateAI

Uncertain

0.71

PROVEAN

Uncertain

-3.5

D;D;D;D;D;D;D

REVEL

Pathogenic

0.77

Sift

Benign

0.042

D;D;D;D;D;D;D

Sift4G

Benign

0.062

T;D;D;D;D;T;D

Polyphen

0.97

D;.;.;.;.;.;.

Vest4

0.72

MVP

0.96

MPC

0.35

ClinPred

0.77

GERP RS

5.7

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.85

gMVP

0.77

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.0

Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over