rs730881739

chr3-37020401-G-Achr3-37020401-G-Cchr3-37020401-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM1PM5PP3

The NM_000249.4(MLH1):c.976G>A(p.Val326Met) variant causes a missense change. The variant allele was found at a frequency of 0.00000434 in 1,614,066 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V326A) has been classified as Benign.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000041 ( 0 hom. )

Consequence

MLH1
NM_000249.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:5B:1

Conservation

PhyloP100: 5.47

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 5 ACMG points.

PM1

In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 3 benign, 17 uncertain in NM_000249.4

PM5

Other missense variant is known to change same aminoacid residue: Variant chr3-37020402-T-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 231925.We mark this variant Likely_pathogenic, oryginal submissions are: {Likely_pathogenic=2, Uncertain_significance=1}.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.757

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MLH1	NM_000249.4 linkuse as main transcript	c.976G>A	p.Val326Met	missense_variant	11/19	ENST00000231790.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MLH1	ENST00000231790.8 linkuse as main transcript	c.976G>A	p.Val326Met	missense_variant	11/19	1	NM_000249.4	P1	P40692-1

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152190

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000655

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.00000398

AC:

AN:

251374

Hom.:

AF XY:

0.00000736

AC XY:

AN XY:

135846

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:

0.00

Gnomad OTH exome

AF:

0.000163

GnomAD4 exome

AF:

0.00000410

AC:

AN:

1461876

Hom.:

Cov.:

AF XY:

0.00000550

AC XY:

AN XY:

727240

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000447

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:

0.00000270

Gnomad4 OTH exome

AF:

0.0000166

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152190

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74348

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.0000655

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000403

Hom.:

Bravo

AF:

0.0000151

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:5Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Hereditary cancer-predisposing syndrome

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Nov 15, 2023	The p.V326M variant (also known as c.976G>A), located in coding exon 11 of the MLH1 gene, results from a G to A substitution at nucleotide position 976. The valine at codon 326 is replaced by methionine, an amino acid with highly similar properties. This alteration was identified in a cohort of familial colorectal cancer patients undergoing multigene panel testing (Raskin L et al. Oncotarget, 2017 Nov;8:93450-93463). 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. -
Uncertain significance, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Aug 23, 2022	This missense variant replaces valine with methionine at codon 326 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 observed in an individual affected with colon cancer, whose tumor showed microsatellite stability (PMID: 29212164). This variant has been identified in 1/251374 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, criteria provided, single submitter

clinical testing

PreventionGenetics, part of Exact Sciences

Aug 01, 2023

The MLH1 c.976G>A variant is predicted to result in the amino acid substitution p.Val326Met. This variant was reported as a variant of uncertain significance in a large cohort of individuals with colon cancer (Raskin et al. 2017. PubMed ID: 29212164, supplementary data). This variant was also described in a patient with suspected Lynch syndrome; however, pathogenic variants were identified in other genes in that individual (Infante et al. 2022. PubMed ID: 36232793). This variant is reported in 1 of ~251,000 alleles in the gnomAD public population database (http://gnomad.broadinstitute.org/variant/3-37061892-G-A). At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

May 25, 2018

This variant is denoted MLH1 c.976G>A at the cDNA level, p.Val326Met (V326M) at the protein level, and results in the change of a Valine to a Methionine (GTG>ATG). This variant has not, to our knowledge, been published in the literature as pathogenic or benign. MLH1 Val326Met was not observed at a significant allele frequency in large population cohorts (Lek 2016). Since Valine and Methionine share similar properties, this is considered a conservative amino acid substitution. MLH1 Val326Met is located in the N-terminal ATPase domain (Andersen 2012). In silico analysis, which includes protein predictors and evolutionary conservation, supports that this variant does not alter protein structure/function. Based on currently available evidence, it is unclear whether MLH1 Val326Met is a pathogenic or benign variant. We consider it to be a variant of uncertain significance. -

Hereditary nonpolyposis colorectal neoplasms

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Nov 24, 2023

This sequence change replaces valine, which is neutral and non-polar, with methionine, which is neutral and non-polar, at codon 326 of the MLH1 protein (p.Val326Met). This variant is present in population databases (rs730881739, gnomAD no frequency). This missense change has been observed in individual(s) with colon cancer (PMID: 29212164). ClinVar contains an entry for this variant (Variation ID: 182522). 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) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on MLH1 protein function. 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. -

Colorectal cancer, hereditary nonpolyposis, type 2

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Myriad Genetics, Inc.

Nov 13, 2023

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]. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.21

BayesDel_addAF

Pathogenic

0.23

BayesDel_noAF

Uncertain

0.090

Cadd

Benign

Dann

Uncertain

1.0

DEOGEN2

Uncertain

0.72

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

Eigen

Uncertain

0.41

Eigen_PC

Uncertain

0.45

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Uncertain

0.92

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

M_CAP

Uncertain

0.13

MetaRNN

Pathogenic

0.76

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

MetaSVM

Uncertain

0.52

MutationAssessor

Pathogenic

3.0

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

MutationTaster

Benign

1.0

D;D;D;D;D;D

PrimateAI

Uncertain

0.66

PROVEAN

Benign

-2.4

N;N;N;N;N;N;N

REVEL

Pathogenic

0.76

Sift

Benign

0.11

T;T;T;T;T;T;T

Sift4G

Benign

0.079

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

Polyphen

0.25

B;.;.;.;.;.;.

Vest4

0.68

MVP

0.90

MPC

0.13

ClinPred

0.80

GERP RS

4.9

Varity_R

0.42

gMVP

0.50

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