3-37049003-C-G

Variant names:

• chr3-37049003-C-G
• rs876661149
• NM_000249.4:c.2089C>G

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 4P and 2B. PM1 PM2 BP4_Moderate

The NM_000249.4(MLH1):​c.2089C>G​(p.Leu697Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 13/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. L697F) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: MLH1 NM_000249.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:5
• Conservation: PhyloP100: 2.81
• Publications: 9 publications found

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 Gene-Disease associations (from GenCC):

• Lynch syndrome

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: G2P, ClinGen, Orphanet
• Lynch syndrome 2

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, Genomics England PanelApp
• Muir-Torre syndrome

  Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE, SUPPORTIVE Submitted by: Genomics England PanelApp, Ambry Genetics, G2P, Orphanet
• mismatch repair cancer syndrome 1

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Ambry Genetics, G2P, Labcorp Genetics (formerly Invitae), Orphanet, ClinGen
• Lynch syndrome 1

  Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• ovarian cancer

  Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp
• malignant pancreatic neoplasm

  Inheritance: AD Classification: MODERATE Submitted by: Genomics England PanelApp
• rhabdomyosarcoma

  Inheritance: AR Classification: MODERATE Submitted by: Genomics England PanelApp
• prostate cancer

  Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics
• breast cancer

  Inheritance: AD Classification: NO_KNOWN Submitted by: Ambry Genetics
• hereditary breast carcinoma

  Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

ACMG classification

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 5 benign, 38 uncertain in NM_000249.4
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.20177832).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MLH1	NM_000249.4	c.2089C>G	p.Leu697Val	missense_variant	Exon 18 of 19	ENST00000231790.8	NP_000240.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MLH1	ENST00000231790.8	c.2089C>G	p.Leu697Val	missense_variant	Exon 18 of 19	1	NM_000249.4	ENSP00000231790.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:2

Apr 25, 2025

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.L697V variant (also known as c.2089C>G), located in coding exon 18 of the MLH1 gene, results from a C to G substitution at nucleotide position 2089. The leucine at codon 697 is replaced by valine, an amino acid with highly similar properties. This amino acid position is well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear.

Aug 18, 2018

Color Diagnostics, LLC DBA Color Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Lynch syndrome Uncertain:1

Aug 08, 2023

All of Us Research Program, National Institutes of Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

not provided Uncertain:1

Dec 06, 2015

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is denoted MLH1 c.2089C>G at the cDNA level, p.Leu697Val (L697V) at the protein level, and results in the change of a Leucine to a Valine (CTC>GTC). This variant has not, to our knowledge, been published in the literature as pathogenic or benign. MLH1 Leu697Val was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, suggesting it is not a common benign variant in these populations. Since Leucine and Valine share similar properties, this is considered a conservative amino acid substitution. MLH1 Leu697Val occurs at a position that is conserved through mammals and is located in the Pms1p-interactive domain and region of interaction with PMS2, MLH3, and PMS1 (Pang 1997, Raevaara 2005). In silico analyses are inconsistent regarding the effect this variant may have on protein structure and function. Based on currently available evidence, it is unclear whether MLH1 Leu697Val is pathogenic or benign. We consider it to be a variant of uncertain significance.

Hereditary nonpolyposis colorectal neoplasms Uncertain:1

Jan 29, 2025

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 valine, which is neutral and non-polar, at codon 697 of the MLH1 protein (p.Leu697Val). This variant is not present in population databases (gnomAD no frequency). 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: 234666). Invitae Evidence Modeling incorporating data from in vitro experimental studies (internal data) indicates that this missense variant is not expected to disrupt MLH1 function with a negative predictive value of 95%. 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: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.060
BayesDel_addAF	Uncertain	0.14	D
BayesDel_noAF	Uncertain	-0.030
CADD	Benign	20
DANN	Benign	0.97
DEOGEN2	Uncertain	0.54	D;.;.;.;.;.
Eigen	Benign	-0.11
Eigen_PC	Benign	0.11
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Benign	0.79	T;T;.;.;.;T
M_CAP	Benign	0.024	T
MetaRNN	Benign	0.20	T;T;T;T;T;T
MetaSVM	Benign	-0.35	T
MutationAssessor	Benign	0.52	N;.;.;.;.;.
PhyloP100		2.8
PrimateAI	Benign	0.37	T
PROVEAN	Benign	0.39	N;N;N;N;N;N
REVEL	Uncertain	0.41
Sift	Benign	0.57	T;T;T;T;T;T
Sift4G	Benign	0.50	T;T;T;T;T;T
Vest4		0.39
ClinPred		0.22	T
GERP RS		5.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.16
gMVP		0.34
Mutation Taster		=78/22	polymorphism

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

Other links and lift over

dbSNP: rs876661149; hg19: chr3-37090494;