NM_000249.4:c.277A>G

Variant names:

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 0P and 1B. BP4

The NM_000249.4(MLH1):c.277A>G(p.Ser93Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000646 in 1,611,026 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000064 ( 0 hom. )

Consequence

MLH1
NM_000249.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:5B:11

Conservation

PhyloP100: 0.717

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 -1 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.36136347).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MLH1	NM_000249.4 link	c.277A>G	p.Ser93Gly	missense_variant	Exon 3 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.277A>G	p.Ser93Gly	missense_variant	Exon 3 of 19	1	NM_000249.4	ENSP00000231790.3		P40692-1

Frequencies

GnomAD3 genomes

AF:

0.0000657

AC:

AN:

152224

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

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:

0.000132

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000159

AC:

AN:

251392

Hom.:

AF XY:

0.0000221

AC XY:

AN XY:

135876

show subpopulations

Gnomad AFR exome

AF:

0.0000615

Gnomad AMR exome

AF:

0.00

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:

0.0000176

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000644

AC:

AN:

1458802

Hom.:

Cov.:

AF XY:

0.0000730

AC XY:

AN XY:

726016

show subpopulations

Gnomad4 AFR exome

AF:

0.0000299

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000232

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000739

Gnomad4 OTH exome

AF:

0.000149

GnomAD4 genome

AF:

0.0000657

AC:

AN:

152224

Hom.:

Cov.:

AF XY:

0.0000672

AC XY:

AN XY:

74372

show subpopulations

Gnomad4 AFR

AF:

0.0000241

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:

0.000132

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000539

Hom.:

Bravo

AF:

0.0000718

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000116

AC:

ExAC

AF:

0.0000330

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.0000593

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:5Benign:11

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:3Benign:3

Nov 01, 2024

CeGaT Center for Human Genetics Tuebingen

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

MLH1: PM2 -

Diagnostic Laboratory, Department of Genetics, University Medical Center Groningen

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Mar 30, 2021

GeneDx

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is associated with the following publications: (PMID: 10671064, 11793442, 27300758, 28932927, 11555625, 22753075, 26247049, 16083711, 22949387, 12547705, 14871975, 18415027, 18033691, 17510385, 17210669, 19863800, 20020535, 12513688, 17594722, 21120944, 29575718, 32081490) -

Laboratory of Diagnostic Genome Analysis, Leiden University Medical Center (LUMC)

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Department of Pathology and Laboratory Medicine, Sinai Health System

Significance: Likely benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

The MLH1 p.Ser93Gly variant was identified in 16 of 2132 proband chromosomes (frequency: 0.007) from individuals or families with Lynch syndrome (Barnetson 2008, Jansen 2016, van Puijenbroek 2008, Raevaara 2005). The variant was also identified in dbSNP (ID: rs41295282 as "With Uncertain significance allele"), ClinVar (1x as benign by Invitae; 3x as likely benign by GeneDx, Ambry Genetics, and Mayo Clinic; and 2x as uncertain significance by InSiGHT and Counsyl), MutDB, UMD-LSDB (1x as unclassified variant), Mismatch Repair Genes Variant Database, and Insight Hereditary Tumors database (37x). The variant was not identified in the Gene Insight-COGR, Cosmic, or Zhejiang University databases. The variant was identified in control databases in 6 of 277126 chromosomes at a frequency of 0.00002 (Genome Aggregation Database Feb 27, 2017). The variant was observed in the following populations: African in 1 of 24028 chromosomes (freq: 0.00004), European in 4 of 126634 chromosomes (freq: 0.00003), and South Asian in 1 of 30780 chromosomes (freq: 0.00003), while the variant was not observed in the Other, Latino, Ashkenazi Jewish, East Asian, or Finnish populations. In addition, several functional studies using in vitro Mismatch Repair Assays identify the variant has normal MMR activity (Andersen 2012, Drost 2010, Kansikas 2011, Ou 2007, Takahashi 2007, Thompson 2013, Wanat 2007, Raevaara 2005). However, the variant exhibited reduction of protein efficiency compared to the wild-type, suggesting this may be a low penetrance variant (Vogelsang 2009). The p.Ser93 residue is conserved in mammals but not in more distantly related organisms; however, 4 of 5 computational analyses (PolyPhen-2, SIFT, AlignGVGD, BLOSUM, MutationTaster) do not suggest a high likelihood of impact to the protein; this information is not predictive enough to rule out pathogenicity. The variant occurs outside of the splicing consensus sequence and 3 of 5 in silico or computational prediction software programs (SpliceSiteFinder, MaxEntScan, NNSPLICE, GeneSplicer, HumanSpliceFinder) predict a greater than 10% difference in splicing. However, this information is not predictive enough to assume pathogenicity. In addition, analysis using the pCAS reporter assay showed splice patterns of the variant allele were the same as the wild type (van der Klift 2015). In summary, based on the above information, the clinical significance of this variant cannot be determined with certainty at this time although we would lean towards a more benign role for this variant. This variant is classified as likely benign. -

Aug 11, 2021

Quest Diagnostics Nichols Institute San Juan Capistrano

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not specified

Benign:3

Mar 04, 2025

Center for Genomic Medicine, Rigshospitalet, Copenhagen University Hospital

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jan 23, 2025

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: MLH1 c.277A>G (p.Ser93Gly) results in a non-conservative amino acid change located in the DNA mismatch repair protein family, N-terminal domain and Histidine kinase/HSP90-like ATPase domain of the encoded protein sequence. Three of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 1.6e-05 in 251392 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.277A>G has been reported in the literature in individuals affected with Hereditary Nonpolyposis Colorectal Cancer (Schneider_2018, Jansen_2016, Barnetson _2008, Hendriks _2003, Nystrom-Lahti_2002, Quaresima _1998). These reports do not provide unequivocal conclusions about association of the variant with Lynch Syndrome. Jansen_2016 reports a patient that carried the variant of interest along with another pathogenic germline MUTYH variant, c1187G>A (p.G396D) and a somatic MLH1 variant, c.281delT (p.(S95LfsX13), providing supporting evidence for a benign role. Several functional studies have been performed to assess the variant's impact on interaction and binding with PMS2 and Exo1, MMR activity, nuclear localization and expression, and splice pattern (Andersen_2012, Drost_2010, Takahashi_2007, Wanat_2007, Raevaara_2005, Nystrom-Lahti_2002, Ellison_2001). These studies have consistently shown that mutant protein perform comparably to wild-type function. The following publications have been ascertained in the context of this evaluation (PMID: 11555625, 17510385, 18383312, 18033691, 20020535, 16083711, 19863800, 12547705, 22949387, 17210669, 26247049, 22753075, 27300758, 29575718, 28932927, 11793442, 10671064, 33471991). ClinVar contains an entry for this variant (Variation ID: 90126). Based on the evidence outlined above, the variant was classified as likely benign. -

Mayo Clinic Laboratories, Mayo Clinic

Significance: Likely benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Hereditary cancer-predisposing syndrome

Benign:3

Sep 18, 2021

Sema4, Sema4

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: curation

- -

Sep 11, 2023

Color Diagnostics, LLC DBA Color Health

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Mar 05, 2019

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. -

Colorectal cancer, hereditary nonpolyposis, type 2

Uncertain:1Benign:1

Dec 08, 2015

Counsyl

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Dec 12, 2023

Myriad Genetics, Inc.

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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]. -

Breast and/or ovarian cancer

Uncertain:1

Feb 14, 2022

CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Hereditary nonpolyposis colorectal neoplasms

Benign:1

Feb 04, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.073

BayesDel_addAF

Uncertain

0.13

BayesDel_noAF

Uncertain

0.13

CADD

Benign

DANN

Uncertain

0.99

DEOGEN2

Uncertain

0.73

Eigen

Benign

-0.55

Eigen_PC

Benign

-0.58

FATHMM_MKL

Benign

0.067

LIST_S2

Uncertain

0.95

M_CAP

Uncertain

0.25

MetaRNN

Benign

0.36

MetaSVM

Uncertain

0.18

MutationAssessor

Uncertain

2.3

PrimateAI

Benign

0.30

PROVEAN

Uncertain

-2.8

REVEL

Uncertain

0.55

Sift

Uncertain

0.025

Sift4G

Uncertain

0.038

Polyphen

0.019

Vest4

0.42

MVP

0.99

MPC

0.066

ClinPred

0.26

GERP RS

0.36

Varity_R

0.15

gMVP

0.39

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.030

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