rs63751448

Positions:

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM5PP3_Moderate

The NM_000249.4(MLH1):c.794G>A(p.Arg265His) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000725 in 1,613,572 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 12/21 in silico tools predict a damaging 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. R265C) has been classified as Pathogenic.

Frequency

Genomes: 𝑓 0.000046 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000075 ( 0 hom. )

Consequence

MLH1
NM_000249.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:13B:4

Conservation

PhyloP100: 9.59

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 4 ACMG points.

PM5

Other missense variant is known to change same aminoacid residue: Variant chr3-37017508-C-T is described in Lovd as [Pathogenic].

PP3

MetaRNN computational evidence supports a deleterious effect, 0.875

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MLH1	NM_000249.4 linkuse as main transcript	c.794G>A	p.Arg265His	missense_variant	10/19	ENST00000231790.8	NP_000240.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MLH1	ENST00000231790.8 linkuse as main transcript	c.794G>A	p.Arg265His	missense_variant	10/19	1	NM_000249.4	ENSP00000231790	P1	P40692-1

Frequencies

GnomAD3 genomes

AF:

0.0000461

AC:

AN:

151988

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:

0.000103

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000477

AC:

AN:

251462

Hom.:

AF XY:

0.0000589

AC XY:

AN XY:

135900

show subpopulations

Gnomad AFR exome

AF:

0.0000615

Gnomad AMR exome

AF:

0.0000578

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.0000327

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000703

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000753

AC:

110

AN:

1461584

Hom.:

Cov.:

AF XY:

0.0000660

AC XY:

AN XY:

727114

show subpopulations

Gnomad4 AFR exome

AF:

0.0000597

Gnomad4 AMR exome

AF:

0.0000447

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000116

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000935

Gnomad4 OTH exome

AF:

0.0000166

GnomAD4 genome

AF:

0.0000461

AC:

AN:

151988

Hom.:

Cov.:

AF XY:

0.0000539

AC XY:

AN XY:

74238

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:

0.000103

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000450

Hom.:

Bravo

AF:

0.0000453

TwinsUK

AF:

0.000270

AC:

ALSPAC

AF:

0.000259

AC:

ExAC

AF:

0.0000330

AC:

EpiCase

AF:

0.000109

EpiControl

AF:

0.0000593

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:13Benign:4

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not specified

Uncertain:3Benign:1

Uncertain significance, criteria provided, single submitter	clinical testing	Department of Pathology and Laboratory Medicine, Sinai Health System	Dec 05, 2014	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine	Jun 16, 2016	Variant identified in a genome or exome case(s) and assessed due to predicted null impact of the variant or pathogenic assertions in the literature or databases. Disclaimer: This variant has not undergone full assessment. The following are preliminary notes: 13 papers in HGMD, however several of these call pathogenicity into question. ClinVar: 3 VUS (including expert panel - no new evidence since this classification), 1 LB -
Likely benign, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Nov 20, 2023	Variant summary: MLH1 c.794G>A (p.Arg265His) results in a non-conservative amino acid change located in the DNA mismatch repair protein family, N-terminal domain of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 4.8e-05 in 251462 control chromosomes. This frequency is not significantly higher than estimated for a pathogenic variant in MLH1 causing Hereditary Nonpolyposis Colorectal Cancer/Lynch syndrome (4.8e-05 vs 0.00071), allowing no conclusion about variant significance. c.794G>A has been reported in the literature in individuals affected with Lynch Syndrome (example, Pastrello_2011, Tournier_2008). Two families reported in Pastrello_2011, identified the variant to co-occur with a pathogenic MLH1 variant, c.1011delC (p.Asn338fs). In addition, one of the families showed the variant of interest to lack cosegregation with disease. Tournier_2008 also reports the variant to co-occur with another pathogenic MLH1 variant, c.1989G>T (p.Glu663Asp). The reported co-occurrences with other pathogenic variant(s) (MLH1 c.1989G>T, p.Glu663Asp; MLH1 c.1011delC, p.Asn338fs) and the lack of segregation with disease, provide supporting evidence for a benign role. Several publications reporting experimental evidence with conflicting interpretations with some showing no impact of the variant on protein function and mismatch repair (MMR) activity, while others do report reduced MMR efficiency (Hinrichsen_2013, Borras_2012, Martinez_2010, Zhao_2008, Takahashi_2007, Wanat_2007, Kondo_2003, Trojan_2002, Ellison_2001, Shimodaira_1998). Furthermore, conflicting experimental evidence was observed in regards to RNA splicing with indications of varying levels of exon 10 skipping to no effect (Soukarieh_2016, Borras_2012, Pastrello_2011, Tournier_2008). The following publications have been ascertained in the context of this evaluation (PMID: 22736432, 18383312, 11555625, 10573010, 23403630, 12810663, 28492532, 21239990, 9697702, 26761715, 17510385, 18561205, 11781295, 8993976, 17210669, 26580448, 18373977). Multiple submitters have cited clinical-significance assessments for this variant to ClinVar after 2014 with conflicting assessments. Some submitters cite overlapping evidence utilized in the context of this evaluation and at-least one submitter has re-classified this variant as likely benign since our previous evaluation. Based on the evidence outlined above, the variant was classified as likely benign. -
Uncertain significance, criteria provided, single submitter	clinical testing	Center for Genomic Medicine, Rigshospitalet, Copenhagen University Hospital	Aug 15, 2023	- -

Hereditary cancer-predisposing syndrome

Uncertain:2Benign:2

Likely benign, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Jun 14, 2016	- -
Uncertain significance, no assertion criteria provided	clinical testing	True Health Diagnostics	Nov 01, 2017	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Institute for Biomarker Research, Medical Diagnostic Laboratories, L.L.C.	Nov 06, 2023	- -
Likely benign, criteria provided, single submitter	clinical testing	Ambry Genetics	May 21, 2020	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. -

not provided

Uncertain:3

Uncertain significance, criteria provided, single submitter	clinical testing	Quest Diagnostics Nichols Institute San Juan Capistrano	Dec 21, 2018	- -
Uncertain significance, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Dec 01, 2021	- -
Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Apr 23, 2024	Published functional studies demonstrate normal protein expression and partial to no impact on mismatch repair function (PMID: 9697702, 11555625, 12810663, 17510385, 23403630); RNA studies and/or minigene assays demonstrate an incomplete splice effect resulting in exon skipping (PMID: 18561205, 26761715); Observed in individuals with MLH1-related cancers, occurring on the same allele (in cis) with a truncating MLH1 variant in one family (PMID: 8993976, 18561205); 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: 22736432, 20176959, 23403630, 25525159, 28492532, 10573010, 31697235, 21239990, 12810663, 17510385, 11781295, 17210669, 17594722, 9697702, 25871441, 18205192, 16830052, 17192056, 23741719, 18373977, 11555625, 8993976, 9827806, 28668638, 29520894, 19339519, 22290698, 32170000, 33326660, 35731023, 31332305, 30623411, 32133419, 18383312, 37240284, 26580448, 18561205, 26761715, 22753075, 25085752) -

Colorectal cancer, hereditary nonpolyposis, type 2

Uncertain:1Benign:1

Likely benign, criteria provided, single submitter	clinical testing	Myriad Genetics, Inc.	Mar 14, 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: 25085752]. -
Uncertain significance, criteria provided, single submitter	clinical testing	Counsyl	Nov 24, 2015	- -

Hereditary nonpolyposis colon cancer

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Cancer Variant Interpretation Group UK, Institute of Cancer Research, London

Mar 12, 2019

Data included in classification: Predicted deleterious on SIFT, Polyphen, Align GVGD; Polyphen HumVar (PP3_sup). Three other variants at this position p.(Arg265Ser) and p.(Arg265Pro) and p.(Arg265Cys) all classed as likely pathogenic/pathogenic by InSiGHT. All of these have sufficient additional evidence (RNA studies / segregation / multiple cases / MSI / IHC) to support the classifications (PM5_mod). Additional information (not included in classification): 2 UK families. UK Family 1: Proband: Breast cancer at 42, Mucinous ovarian cancer. IHC: normal. Mother: Colorectal cancer at 74. IHC: normal. UK Family 2: Proband: Right sided bowel cancer age 51, Loss of MSH6 and MSH2 on IHC and MSI-High. Proband also had pathogenic MSH2. Literature (as per INSIGHT): 2 Italian families: In both variant is in cis with frameshift variant (Viel et al 1997, Genuardi et al 1999, Pastrello et al, 2011). 1 French family: Variant in trans with pathogenic MLH1 variant (Tournier et al 2008). Controls: The variant was observed 8/56,871 GNOMAD NFE controls and 4/68,860 individuals in the remainder of the GNOMAD population. Splicing data: Splicing predictions equivocal. Splicing functional data conflicting: (some functional affect on splicing: PMID 17510385, 18561205, 25525159, no effect/minimal effect PMID 9697702, 12810663, 23403630). Other classifications: Multiple classifications of VUS in ClinVar. -

MLH1-related disorder

Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

PreventionGenetics, part of Exact Sciences

Apr 05, 2024

The MLH1 c.794G>A variant is predicted to result in the amino acid substitution p.Arg265His. This variant was reported to occur in cis with a MLH1 truncating variant in two siblings with colorectal cancer and a family history of colorectal cancer in their father (See family A-PD1 Genuardi et al. 1999. PubMed ID 10573010; Viel et al. 1997. PubMed ID 8993976; confirmed in cis with c.1011delC in Pastrello C et al 2011. PubMed ID: 21239990). The c.794G>A was also reported in a patient with breast cancer and family history of breast cancer (See Pt 85 in Felicio PS et al 2020. PubMed ID: 33326660). This variant has been reported in some studies to have no effect on protein function (Shimodaira et al. 1998. PubMed ID 9697702; Trojan J et al 2002. PubMed ID: 11781295; Kondo E et al 2003. PubMed ID: 12810663); however, in other studies is associated with a mild protein defect (Ellison AR et al 2001. PubMed ID: 11555625; Wanat JJ et al 2007. PubMed ID: 17210669; Takahashi M et al 2007. PubMed ID: 17510385; Hinrichsen I et al 2013. PubMed ID: 23403630). Studies assessing splicing impacts of this variant have indicated it may impact normal splicing (predicted exon 10 skipping in Tournier I et al 2008. PubMed ID: 18561205; Soukarieh O et al 2016. PubMed ID: 26761715). This variant is reported in 0.0070% of alleles in individuals of European (Non-Finnish) descent in gnomAD and has conflicting interpretations regarding its pathogenicity in ClinVar, ranging from likely benign to uncertain significance (https://www.ncbi.nlm.nih.gov/clinvar/variation/90381/). 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

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 31, 2024

This sequence change replaces arginine, which is basic and polar, with histidine, which is basic and polar, at codon 265 of the MLH1 protein (p.Arg265His). This variant is present in population databases (rs63751448, gnomAD 0.007%). This missense change has been observed in individual(s) with clinical features of Lynch syndrome (PMID: 8993976, 18561205; Invitae). ClinVar contains an entry for this variant (Variation ID: 90381). 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 expected to disrupt MLH1 protein function with a positive predictive value of 95%. Experimental studies have shown that this missense change does not substantially affect MLH1 function (PMID: 9697702, 11781295, 12810663, 17510385, 23403630). Studies have shown this missense change is associated with skipping of exon 10 and/or skipping of exons 10-11, but one or more of the resulting mRNA isoform(s) may be naturally occurring (PMID: 30623411, 31332305, 32133419; Invitae). 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. -

Hereditary breast ovarian cancer syndrome

Uncertain:1

Uncertain significance, criteria provided, single submitter

research

Molecular Oncology Research Center, Barretos Cancer Hospital

Jan 25, 2024

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.98

BayesDel_addAF

Pathogenic

0.45

BayesDel_noAF

Pathogenic

0.60

CADD

Pathogenic

DANN

Pathogenic

1.0

DEOGEN2

Pathogenic

0.87

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

Eigen

Pathogenic

0.83

Eigen_PC

Pathogenic

0.81

FATHMM_MKL

Pathogenic

1.0

LIST_S2

Uncertain

0.89

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

M_CAP

Pathogenic

0.61

MetaRNN

Pathogenic

0.88

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

MetaSVM

Uncertain

0.79

MutationAssessor

Pathogenic

4.5

H;.;.;.;.;.;.

MutationTaster

Benign

1.0

D;D;D;D;D;D

PrimateAI

Uncertain

0.67

PROVEAN

Pathogenic

-5.0

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

REVEL

Pathogenic

0.82

Sift

Pathogenic

0.0

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

Sift4G

Pathogenic

0.0

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

Polyphen

1.0

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

Vest4

0.94

MutPred

0.33

Loss of MoRF binding (P = 0.1065);.;.;.;.;.;.;

MVP

0.99

MPC

0.45

ClinPred

1.0

GERP RS

5.7

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.0

Varity_R

0.92

gMVP

0.84

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.080

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