NM_000249.4:c.1675C>A

Variant names:

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM1PM2PM5

The NM_000249.4(MLH1):c.1675C>A(p.Leu559Met) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000131 in 152,194 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. L559P) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)

Exomes 𝑓: 6.9e-7 ( 0 hom. )

Failed GnomAD Quality Control

Consequence

MLH1
NM_000249.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3B:1

Conservation

PhyloP100: 2.16

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 Likely_pathogenic. Variant got 6 ACMG points.

PM1

In a helix (size 14) in uniprot entity MLH1_HUMAN there are 9 pathogenic changes around while only 1 benign (90%) in NM_000249.4

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr3-37042276-T-C is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MLH1	NM_000249.4 link	c.1675C>A	p.Leu559Met	missense_variant	Exon 15 of 19	ENST00000231790.8	NP_000240.1	P40692-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MLH1	ENST00000231790.8 link	c.1675C>A	p.Leu559Met	missense_variant	Exon 15 of 19	1	NM_000249.4	ENSP00000231790.3		P40692-1

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152194

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:

0.0000294

Gnomad OTH

AF:

0.00

GnomAD4 exome

Data not reliable, filtered out with message: AS_VQSR

AF:

6.89e-7

AC:

AN:

1451272

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

722744

show subpopulations

Gnomad4 AFR exome

AF:

0.00

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:

9.07e-7

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152194

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74346

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:

0.0000294

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.00000756

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Hereditary cancer-predisposing syndrome

Uncertain:1Benign:1

Jun 13, 2023

Ambry Genetics

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. -

Aug 24, 2021

Color Diagnostics, LLC DBA Color Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces leucine with methionine at codon 559 of the MLH1 protein. Computational prediction tools and conservation analyses are inconclusive regarding the impact of this variant on the protein function. Computational splicing tools suggest that this variant may not impact RNA splicing. To our knowledge, functional assays have not been performed for this variant nor has this variant been reported in individuals affected with hereditary cancer in the literature. This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD) and has been report in a healthy control individual (PMID: 33309985). 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. -

not provided

Uncertain:1

Sep 16, 2015

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is denoted MLH1 c.1675C>A at the cDNA level, p.Leu559Met (L559M) at the protein level, and results in the change of a Leucine to a Methionine (CTG>ATG). This variant has not, to our knowledge, been published in the literature as pathogenic or benign. MLH1 Leu559Met was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. Since Leucine and Methionine share similar properties, this is considered a conservative amino acid substitution. MLH1 Leu559Met occurs at a position that is conserved across species, with Methionine being the naturally occurring amino acid in one species, and is located in the PMS2/MLH3/PMS1/EXO1 interaction domain (Raevaara 2005, Tournier 2008). In silico analyses predict that this variant is probably damaging to protein structure and function. Based on currently available information, it is unclear whether MLH1 Leu559Met is pathogenic or benign. We consider it to be a variant of uncertain significance. -

Hereditary nonpolyposis colorectal neoplasms

Uncertain:1

Feb 14, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces leucine, which is neutral and non-polar, with methionine, which is neutral and non-polar, at codon 559 of the MLH1 protein (p.Leu559Met). 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. This variant disrupts the p.Leu559 amino acid residue in MLH1. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 21404117). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt MLH1 protein function. ClinVar contains an entry for this variant (Variation ID: 418304). This variant has not been reported in the literature in individuals affected with MLH1-related conditions. This variant is not present in population databases (gnomAD no frequency). -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.11

BayesDel_addAF

Pathogenic

0.21

BayesDel_noAF

Uncertain

0.060

CADD

Benign

DANN

Uncertain

0.99

DEOGEN2

Uncertain

0.76

D;.;.;.;.;.

Eigen

Uncertain

0.26

Eigen_PC

Uncertain

0.26

FATHMM_MKL

Uncertain

0.95

LIST_S2

Uncertain

0.88

D;D;.;.;.;D

M_CAP

Uncertain

0.13

MetaRNN

Uncertain

0.67

D;D;D;D;D;D

MetaSVM

Benign

-0.57

MutationAssessor

Uncertain

2.2

M;.;.;.;.;.

PrimateAI

Uncertain

0.79

PROVEAN

Benign

-1.4

N;N;N;N;N;N

REVEL

Pathogenic

0.70

Sift

Benign

0.045

D;T;D;D;D;T

Sift4G

Uncertain

0.054

T;T;T;T;T;T

Polyphen

0.89

P;.;.;.;.;.

Vest4

0.72

MutPred

0.48

Gain of sheet (P = 0.0827);.;.;.;.;.;

MVP

0.87

MPC

0.23

ClinPred

0.85

GERP RS

3.7

Varity_R

0.58

gMVP

0.59

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.070

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