3-37020402-T-C

Variant names:

Variant summary

Our verdict is Benign. Variant got -17 ACMG points: 0P and 17B. BP4BP6_Very_StrongBS1BS2

The NM_000249.4(MLH1):c.977T>C(p.Val326Ala) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000579 in 1,614,136 control chromosomes in the GnomAD database, including 4 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Benign (★★★).

Frequency

Genomes: 𝑓 0.00043 ( 2 hom., cov: 33)

Exomes 𝑓: 0.00059 ( 2 hom. )

Consequence

MLH1
NM_000249.4 missense

Scores

Clinical Significance

Benign reviewed by expert panel U:2B:27O:1

Conservation

PhyloP100: 7.64

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 Benign. Variant got -17 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.41998726).

BP6

Variant 3-37020402-T-C is Benign according to our data. Variant chr3-37020402-T-C is described in ClinVar as [Benign]. Clinvar id is 42496.Status of the report is reviewed_by_expert_panel, 3 stars. Variant chr3-37020402-T-C is described in Lovd as [Likely_benign]. Variant chr3-37020402-T-C is described in Lovd as [Benign]. Variant chr3-37020402-T-C is described in Lovd as [Pathogenic].

BS1

Variant frequency is greater than expected in population sas. gnomad4 allele frequency = 0.000433 (66/152256) while in subpopulation SAS AF= 0.00166 (8/4824). AF 95% confidence interval is 0.000825. There are 2 homozygotes in gnomad4. There are 25 alleles in male gnomad4 subpopulation. Median coverage is 33. This position pass quality control queck.

BS2

High Homozygotes in GnomAd4 at 2 AD,AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MLH1	NM_000249.4 link	c.977T>C	p.Val326Ala	missense_variant	Exon 11 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.977T>C	p.Val326Ala	missense_variant	Exon 11 of 19	1	NM_000249.4	ENSP00000231790.3		P40692-1

Frequencies

GnomAD3 genomes

AF:

0.000440

AC:

AN:

152138

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000145

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000654

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00166

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.0127

Gnomad NFE

AF:

0.000706

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.000469

AC:

118

AN:

251388

Hom.:

AF XY:

0.000611

AC XY:

AN XY:

135862

show subpopulations

Gnomad AFR exome

AF:

0.000123

Gnomad AMR exome

AF:

0.000260

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00111

Gnomad FIN exome

AF:

0.0000462

Gnomad NFE exome

AF:

0.000607

Gnomad OTH exome

AF:

0.000489

GnomAD4 exome

AF:

0.000594

AC:

868

AN:

1461880

Hom.:

Cov.:

AF XY:

0.000671

AC XY:

488

AN XY:

727246

show subpopulations

Gnomad4 AFR exome

AF:

0.0000896

Gnomad4 AMR exome

AF:

0.000268

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00140

Gnomad4 FIN exome

AF:

0.0000187

Gnomad4 NFE exome

AF:

0.000606

Gnomad4 OTH exome

AF:

0.000596

GnomAD4 genome

AF:

0.000433

AC:

AN:

152256

Hom.:

Cov.:

AF XY:

0.000336

AC XY:

AN XY:

74448

show subpopulations

Gnomad4 AFR

AF:

0.000144

Gnomad4 AMR

AF:

0.0000654

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00166

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.000691

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.000511

Hom.:

Bravo

AF:

0.000400

TwinsUK

AF:

0.000539

AC:

ALSPAC

AF:

0.000259

AC:

ESP6500AA

AF:

0.000227

AC:

ESP6500EA

AF:

0.00116

AC:

ExAC

AF:

0.000527

AC:

EpiCase

AF:

0.00109

EpiControl

AF:

0.000711

ClinVar

Significance: Benign

Submissions summary: Uncertain:2Benign:27Other:1

Revision: reviewed by expert panel

LINK: link

Submissions by phenotype

not specified

Benign:8Other:1

not provided, no classification provided	reference population	ITMI	Sep 19, 2013	- -
Benign, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Nov 05, 2020	Variant summary: The variant, MLH1 c.977T>C (p.Val326Ala) results in a non-conservative amino acid change located in the DNA mismatch repair protein, S5 domain 2-like 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 0.00048 in 278288 control chromosomes, predominantly at a frequency of 0.0011 within the South Asian subpopulation in the gnomAD database, including 1 homozygote. The observed variant frequency within South Asian control individuals in the gnomAD database is approximately 1.6 fold of the estimated maximal expected allele frequency for a pathogenic variant in MLH1 causing Lynch Syndrome phenotype (0.00071), strongly suggesting that the variant is a benign polymorphism found primarily in populations of South Asian origin. This variant was found in two affected members from a Lynch family (example, Hardt 2011). Detailed genotypic and phenotypic information was not available to assert whether or not the variant co-segregated with disease. In contrast, in one family, this variant did not co-segregate with the disease: while one affected member was positive for the variant, other two affected members did not carry the variant (Pastrello 2011). In addition, tumor tissues from patients with this variant showed no loss of heterozygosity, normal expression of MLH1 or MSH2, and normal microsatellite instability (Dieumegard 2000, Spaepen 2006, Pastrello 2011, Hardt 2011). In vitro MMR and dominant mutator effect studies showed conflicting results (Shimodaira 1998, Trojan 2002, Takahashi 2007) although supporting a functional MMR activity (Trojan_2002). Furthermore, a yeast two-hybrid assay showed that hMLH1 V326A can interact with hPMS2 and hEXO1 (Kondo 2003) and the variant was shown to not affect normal splicing (Borras 2012). Twelve clinical diagnostic laboratories and one expert panel (INSIGHT) have submitted clinical-significance assessments for this variant to ClinVar without evidence for independent evaluation. Eleven of them, to include the expert panel have classified the variant as likely benign/benign. Based on the evidence outlined above, the variant was classified as benign. -
Benign, no assertion criteria provided	clinical testing	Genome Diagnostics Laboratory, University Medical Center Utrecht	-	- -
Benign, criteria provided, single submitter	clinical testing	Quest Diagnostics Nichols Institute San Juan Capistrano	Aug 13, 2021	- -
Likely benign, criteria provided, single submitter	clinical testing	Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine	Jul 27, 2017	proposed classification - variant undergoing re-assessment, contact laboratory -
Benign, criteria provided, single submitter	clinical testing	Center for Genomic Medicine, Rigshospitalet, Copenhagen University Hospital	Mar 04, 2025	- -
Benign, no assertion criteria provided	clinical testing	Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+	-	- -
Likely benign, no assertion criteria provided	clinical testing	Mayo Clinic Laboratories, Mayo Clinic	-	- -
Benign, no assertion criteria provided	clinical testing	Laboratory of Diagnostic Genome Analysis, Leiden University Medical Center (LUMC)	-	- -

not provided

Benign:6

Likely benign, no assertion criteria provided	clinical testing	Genome Diagnostics Laboratory, Amsterdam University Medical Center	-	- -
Benign, criteria provided, single submitter	not provided	Breakthrough Genomics, Breakthrough Genomics	-	- -
Likely benign, criteria provided, single submitter	clinical testing	PreventionGenetics, part of Exact Sciences	Feb 13, 2017	- -
Likely benign, criteria provided, single submitter	clinical testing	ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories	Nov 11, 2023	- -
Likely benign, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Feb 01, 2025	MLH1: BS1 -
Likely benign, criteria provided, single submitter	clinical testing	GeneDx	Apr 09, 2021	This variant is associated with the following publications: (PMID: 8574961, 22949387, 9697702, 20176959, 18561205, 10573010, 16736289, 8592341, 16885385, 10446963, 9506527, 10448273, 17594722, 24728327, 23588873, 25637381, 22736432, 24055113, 25871441, 10732761, 21239990, 12810663, 17510385, 21404117, 11781295, 11555625, 17192056, 22290698, 15340264, 10601588, 26976419, 24362816, 20533529, 30998989) -

Hereditary cancer-predisposing syndrome

Benign:5

Benign, criteria provided, single submitter	clinical testing	Institute for Biomarker Research, Medical Diagnostic Laboratories, L.L.C.	Dec 20, 2022	- -
Likely benign, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Apr 03, 2015	- -
Likely benign, criteria provided, single submitter	clinical testing	Ambry Genetics	Sep 28, 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. -
Likely benign, no assertion criteria provided	clinical testing	True Health Diagnostics	Sep 27, 2018	- -
Benign, criteria provided, single submitter	curation	Sema4, Sema4	Oct 21, 2020	- -

Lynch syndrome

Uncertain:1Benign:2

Benign, reviewed by expert panel	research	International Society for Gastrointestinal Hereditary Tumours (InSiGHT)	Sep 05, 2013	Multifactorial likelihood analysis posterior probability <0.001 -
Uncertain significance, flagged submission	clinical testing	Genomic Diagnostic Laboratory, Division of Genomic Diagnostics, Children's Hospital of Philadelphia	Dec 21, 2015	- -
Likely benign, criteria provided, single submitter	clinical testing	All of Us Research Program, National Institutes of Health	Sep 23, 2024	- -

Colorectal cancer, hereditary nonpolyposis, type 2

Benign:2

Benign, criteria provided, single submitter	clinical testing	KCCC/NGS Laboratory, Kuwait Cancer Control Center	Jul 07, 2023	- -
Likely benign, criteria provided, single submitter	clinical testing	Mendelics	May 28, 2019	- -

Colorectal cancer, non-polyposis

Uncertain:1

Uncertain significance, no assertion criteria provided

research

CSER _CC_NCGL, University of Washington

Jun 01, 2014

- -

Breast and/or ovarian cancer

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

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

Mar 03, 2023

- -

Lynch syndrome 1

Benign:1

Likely benign, no assertion criteria provided

clinical testing

Pathway Genomics

Jul 24, 2014

- -

Muir-Torré syndrome

Benign:1

Benign, criteria provided, single submitter

clinical testing

KCCC/NGS Laboratory, Kuwait Cancer Control Center

Feb 01, 2025

- -

Hereditary nonpolyposis colorectal neoplasms

Benign:1

Benign, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Feb 03, 2025

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.58

BayesDel_addAF

Uncertain

0.15

BayesDel_noAF

Pathogenic

0.40

CADD

Uncertain

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.82

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

Eigen

Uncertain

0.68

Eigen_PC

Pathogenic

0.69

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.88

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

M_CAP

Uncertain

0.092

MetaRNN

Benign

0.42

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

MetaSVM

Uncertain

0.59

MutationAssessor

Pathogenic

3.4

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

PrimateAI

Uncertain

0.65

PROVEAN

Uncertain

-3.9

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

REVEL

Pathogenic

0.86

Sift

Uncertain

0.0020

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

Sift4G

Uncertain

0.0030

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

Polyphen

0.62

P;.;.;.;.;.;.

Vest4

0.78

MVP

0.98

MPC

0.17

ClinPred

0.15

GERP RS

5.8

Varity_R

0.71

gMVP

0.58

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