rs147342421

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM1PM5PP3

The NM_000249.4(MLH1):c.144A>C(p.Gln48His) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000062 in 1,613,854 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. Q48P) has been classified as Likely pathogenic.

Frequency

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

Exomes 𝑓: 0.0000055 ( 0 hom. )

Consequence

MLH1
NM_000249.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:6

Conservation

PhyloP100: 1.89

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 5 ACMG points.

PM1

In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 16 uncertain in NM_000249.4

PM5

Other missense variant is known to change same aminoacid residue: Variant chr3-36996645-A-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 89739.Status of the report is reviewed_by_expert_panel, 3 stars.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.778

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MLH1	NM_000249.4 linkuse as main transcript	c.144A>C	p.Gln48His	missense_variant	2/19	ENST00000231790.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MLH1	ENST00000231790.8 linkuse as main transcript	c.144A>C	p.Gln48His	missense_variant	2/19	1	NM_000249.4	P1	P40692-1

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152206

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000482

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000159

AC:

AN:

251454

Hom.:

AF XY:

0.00000736

AC XY:

AN XY:

135906

show subpopulations

Gnomad AFR exome

AF:

0.000246

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:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000547

AC:

AN:

1461648

Hom.:

Cov.:

AF XY:

0.00000275

AC XY:

AN XY:

727136

show subpopulations

Gnomad4 AFR exome

AF:

0.000119

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:

0.00000360

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152206

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74350

show subpopulations

Gnomad4 AFR

AF:

0.0000482

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:

0.00

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000370

Hom.:

Bravo

AF:

0.0000151

ESP6500AA

AF:

0.000227

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.00000824

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:6

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Colorectal cancer, hereditary nonpolyposis, type 2

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Counsyl	May 15, 2018	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Myriad Genetics, Inc.	Mar 10, 2023	This variant is classified as a variant of uncertain significance as there is insufficient evidence to determine its impact on protein function and/or cancer risk. -

Hereditary cancer-predisposing syndrome

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	May 18, 2023	The p.Q48H variant (also known as c.144A>C), located in coding exon 2 of the MLH1 gene, results from an A to C substitution at nucleotide position 144. The glutamine at codon 48 is replaced by histidine, an amino acid with highly similar properties. This alteration was identified in a cohort of 1260 individuals undergoing panel testing for Lynch syndrome due to having a diagnosis of a Lynch-associated cancer and/or polyps (Yurgelun MB et al. Gastroenterology, 2015 Sep;149:604-13.e20). This amino acid position is highly 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. -
Uncertain significance, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Jun 05, 2019	- -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Jul 26, 2023

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Observed in an individual undergoing multi-gene cancer panel testing due to a personal history of a Lynch syndrome-related cancer and/or polyps (Yurgelun et al., 2015); This variant is associated with the following publications: (PMID: 22753075, 25980754) -

Hereditary nonpolyposis colorectal neoplasms

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jun 23, 2023

This missense change has been observed in individual(s) with clinical features of Lynch syndrome (PMID: 25980754). This sequence change replaces glutamine, which is neutral and polar, with histidine, which is basic and polar, at codon 48 of the MLH1 protein (p.Gln48His). This variant is present in population databases (rs147342421, gnomAD 0.01%). ClinVar contains an entry for this variant (Variation ID: 449060). 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) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on MLH1 protein function. This variant disrupts the p.Gln48 amino acid residue in MLH1. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 19386570, 21404117, 22395473, 24362816). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. 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. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.20

BayesDel_addAF

Pathogenic

0.26

BayesDel_noAF

Pathogenic

0.37

Cadd

Uncertain

Dann

Uncertain

1.0

DEOGEN2

Uncertain

0.73

Eigen

Uncertain

0.49

Eigen_PC

Uncertain

0.43

FATHMM_MKL

Uncertain

0.87

LIST_S2

Uncertain

0.94

M_CAP

Pathogenic

0.34

MetaRNN

Pathogenic

0.78

MetaSVM

Pathogenic

0.80

MutationAssessor

Benign

1.5

MutationTaster

Benign

1.0

D;D;D;D;D;D

PrimateAI

Uncertain

0.62

PROVEAN

Uncertain

-3.2

REVEL

Pathogenic

0.82

Sift

Uncertain

0.0010

Sift4G

Uncertain

0.011

Polyphen

1.0

Vest4

0.57

MutPred

0.52

Loss of ubiquitination at K43 (P = 0.0638);

MVP

0.98

MPC

0.39

ClinPred

0.87

GERP RS

2.3

Varity_R

0.73

gMVP

0.73

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