rs779759678

Variant summary

Our verdict is Likely benign. Variant got -5 ACMG points: 0P and 5B. BP4_StrongBP6

The NM_000249.4(MLH1):c.9C>G(p.Phe3Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000167 in 1,614,080 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another nucleotide change resulting in same amino acid change has been previously reported as Likely benignin ClinVar. Synonymous variant affecting the same amino acid position (i.e. F3F) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000033 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000015 ( 0 hom. )

Consequence

MLH1
NM_000249.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:6B:3

Conservation

PhyloP100: -1.48

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_benign. Variant got -5 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.041897535).

BP6

Variant 3-36993556-C-G is Benign according to our data. Variant chr3-36993556-C-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 185790.We mark this variant Likely_benign, oryginal submissions are: {Uncertain_significance=6, Likely_benign=3}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MLH1	NM_000249.4 linkuse as main transcript	c.9C>G	p.Phe3Leu	missense_variant	1/19	ENST00000231790.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MLH1	ENST00000231790.8 linkuse as main transcript	c.9C>G	p.Phe3Leu	missense_variant	1/19	1	NM_000249.4	P1	P40692-1

Frequencies

GnomAD3 genomes

AF:

0.0000328

AC:

AN:

152218

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:

0.00000398

AC:

AN:

251472

Hom.:

AF XY:

0.00

AC XY:

AN XY:

135922

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:

0.00000879

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000150

AC:

AN:

1461862

Hom.:

Cov.:

AF XY:

0.0000179

AC XY:

AN XY:

727236

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000252

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000180

Gnomad4 OTH exome

AF:

0.0000166

GnomAD4 genome

AF:

0.0000328

AC:

AN:

152218

Hom.:

Cov.:

AF XY:

0.0000403

AC XY:

AN XY:

74364

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:

0.0000712

Hom.:

Bravo

AF:

0.0000113

ExAC

AF:

0.00000824

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:6Benign:3

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not specified

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Nov 15, 2019	Variant summary: MLH1 c.9C>G (p.Phe3Leu) results in a non-conservative amino acid change in the encoded protein sequence. Four of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 4e-06 in 251472 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. To our knowledge, no occurrence of c.9C>G in individuals affected with Hereditary Non-Polyposis Colon Cancer and no experimental evidence demonstrating its impact on protein function have been reported. Four ClinVar submitters (evaluation after 2014) cite the variant as likely benign (n=2) and as uncertain significance (n=2). Based on the evidence outlined above, the variant was classified as uncertain significance. -
Uncertain significance, criteria provided, single submitter	clinical testing	Genetic Services Laboratory, University of Chicago	Aug 16, 2021	DNA sequence analysis of the MLH1 gene demonstrated a sequence change, c.9C>G, in exon 1 that results in an amino acid change, p.Phe3Leu. This sequence change has been described in the gnomAD database with frequency of 0.0023% in the non-Finnish European subpopulation (dbSNP rs779759678). The p.Phe3Leu change affects a poorly conserved amino acid residue located in a domain of the MLH1 protein that is not known to be functional. The p.Phe3Leu substitution appears to be benign using several in-silico pathogenicity prediction tools (SIFT, PolyPhen2, Align GVGD, REVEL). This sequence change does not appear to have been previously described in individuals with MLH1-related disorders. Due to insufficient evidences and the lack of functional studies, the clinical significance of the p.Phe3Leu change remains unknown at this time. -

not provided

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Quest Diagnostics Nichols Institute San Juan Capistrano	Feb 23, 2023	The frequency of this variant in the general population, 0.000023 (3/129188 chromosomes, http://gnomad.broadinstitute.org), is uninformative in assessment of its pathogenicity. In the published literature, the variant has been reported in an unaffected individual in a large pancreatic cancer study (PMID: 32980694 (2020)). In addition, in a large breast cancer study, the variant was reported in an individual with breast cancer as well as in an unaffected individual (PMID: 33471991 (2021), https://databases.lovd.nl/shared/variants/MLH1). 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 benign. Based on the available information, we are unable to determine the clinical significance of this variant. -
Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Mar 17, 2022	Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant does not alter protein structure/function; In-silico analysis is inconclusive as to whether the variant alters gene splicing. In the absence of RNA/functional studies, the actual effect of this sequence change is unknown.; Not observed in any pancreatic cancer cases but was observed in an unaffected control (Mizukami 2020); This variant is associated with the following publications: (PMID: 22753075, 32980694) -

Hereditary cancer-predisposing syndrome

Benign:2

Likely benign, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Aug 14, 2017	- -
Likely benign, criteria provided, single submitter	clinical testing	Ambry Genetics	May 02, 2018	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. -

Colorectal cancer, hereditary nonpolyposis, type 2

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

St. Jude Molecular Pathology, St. Jude Children's Research Hospital

Jul 05, 2022

The MLH1 c.9C>G (p.Phe3Leu) missense change has a maximum subpopulation frequency of 0.0023% in gnomAD v2.1.1 (https://gnomad.broadinstitute.org). The in silico tool REVEL is inconclusive about a pathogenic or benign effect of this variant on protein function, and to our knowledge functional studies have not been performed. To our knowledge, this variant has not been reported in individuals with Lynch syndrome or constitutional mismatch repair deficiency syndrome. In summary, the evidence currently available is insufficient to determine the clinical significance of this variant. It has therefore been classified as of uncertain significance. -

Hereditary nonpolyposis colorectal neoplasms

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jan 24, 2024

This sequence change replaces phenylalanine, which is neutral and non-polar, with leucine, which is neutral and non-polar, at codon 3 of the MLH1 protein (p.Phe3Leu). This variant is present in population databases (rs779759678, gnomAD 0.002%). 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: 185790). 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 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. -

Lynch syndrome

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

All of Us Research Program, National Institutes of Health

Oct 06, 2023

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.14

BayesDel_addAF

Benign

-0.023

BayesDel_noAF

Benign

-0.27

Cadd

Benign

0.017

Dann

Benign

0.82

DEOGEN2

Benign

0.29

Eigen

Benign

-1.4

Eigen_PC

Benign

-1.4

FATHMM_MKL

Benign

0.39

LIST_S2

Benign

0.60

M_CAP

Benign

0.023

MetaRNN

Benign

0.042

MetaSVM

Benign

-0.80

MutationAssessor

Benign

-0.34

MutationTaster

Benign

1.0

PrimateAI

Benign

0.45

PROVEAN

Benign

0.27

REVEL

Uncertain

0.35

Sift

Benign

1.0

Sift4G

Benign

1.0

Polyphen

0.0

Vest4

0.10

MutPred

0.29

Gain of MoRF binding (P = 0.1142);

MVP

0.67

MPC

0.076

ClinPred

0.035

GERP RS

-8.9

Varity_R

0.19

gMVP

0.32

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