NM_000249.4:c.221A>T

Variant names:

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_000249.4(MLH1):c.221A>T(p.Asp74Val) variant causes a missense change. The variant allele was found at a frequency of 0.00000251 in 1,595,140 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

MLH1
NM_000249.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:5B:2

Conservation

PhyloP100: 4.67

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 2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MLH1	NM_000249.4 link	c.221A>T	p.Asp74Val	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.221A>T	p.Asp74Val	missense_variant	Exon 3 of 19	1	NM_000249.4	ENSP00000231790.3		P40692-1

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152166

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:

0.0000294

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.00000398

AC:

AN:

251354

Hom.:

AF XY:

0.00000736

AC XY:

AN XY:

135856

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:

0.00000880

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000139

AC:

AN:

1442974

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

719308

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000183

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152166

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74334

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:

0.0000294

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.0000113

ExAC

AF:

0.00000824

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:5Benign:2

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:2

Apr 25, 2024

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The MLH1 c.221A>T; p.Asp74Val variant (rs751894165, ClinVar Variation ID: 405401), to our knowledge, is not reported in the medical literature in MLH1-related conditions. This variant is only observed on one allele in the Genome Aggregation Database (v2.1.1), indicating it is not a common polymorphism. Computational analyses are uncertain whether this variant is neutral or deleterious (REVEL: 0.624). Due to limited information, the clinical significance of this variant is uncertain at this time. -

Aug 20, 2021

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed at significant frequency in large population cohorts (Lek 2016); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Has not been previously published as pathogenic or benign to our knowledge; This variant is associated with the following publications: (PMID: 22753075) -

Hereditary cancer-predisposing syndrome

Uncertain:2

Aug 22, 2018

Color Diagnostics, LLC DBA Color Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jun 23, 2023

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.D74V variant (also known as c.221A>T), located in coding exon 3 of the MLH1 gene, results from an A to T substitution at nucleotide position 221. The aspartic acid at codon 74 is replaced by valine, an amino acid with highly dissimilar properties. This amino acid position is not well conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Colorectal cancer, hereditary nonpolyposis, type 2

Uncertain:1Benign:1

Oct 25, 2023

Baylor Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Nov 18, 2024

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]. -

Hereditary nonpolyposis colorectal neoplasms

Benign:1

Jan 26, 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

0.12

BayesDel_addAF

Pathogenic

0.29

BayesDel_noAF

Pathogenic

0.17

CADD

Uncertain

DANN

Uncertain

0.98

DEOGEN2

Uncertain

0.76

Eigen

Uncertain

0.20

Eigen_PC

Uncertain

0.28

FATHMM_MKL

Uncertain

0.96

LIST_S2

Pathogenic

0.98

M_CAP

Benign

0.054

MetaRNN

Uncertain

0.62

MetaSVM

Benign

-0.88

MutationAssessor

Benign

0.64

PrimateAI

Uncertain

0.55

PROVEAN

Uncertain

-3.8

REVEL

Uncertain

0.62

Sift

Uncertain

0.027

Sift4G

Benign

0.093

Polyphen

0.25

Vest4

0.62

MutPred

0.50

Loss of ubiquitination at K70 (P = 0.0709);

MVP

0.97

MPC

0.20

ClinPred

0.81

GERP RS

3.5

Varity_R

0.42

gMVP

0.61

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.050

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