14-75049532-C-T

Variant summary

Our verdict is Likely benign. Variant got -4 ACMG points: 0P and 4B. BS2

The NM_001040108.2(MLH3):c.124G>A(p.Ala42Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000483 in 1,614,108 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. A42P) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000033 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000050 ( 0 hom. )

Consequence

MLH3
NM_001040108.2 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:3

Conservation

PhyloP100: 7.84

Variant links:

Genes affected

MLH3 (HGNC:7128): (mutL homolog 3) This gene is a member of the MutL-homolog (MLH) family of DNA mismatch repair (MMR) genes. MLH genes are implicated in maintaining genomic integrity during DNA replication and after meiotic recombination. The protein encoded by this gene functions as a heterodimer with other family members. Somatic mutations in this gene frequently occur in tumors exhibiting microsatellite instability, and germline mutations have been linked to hereditary nonpolyposis colorectal cancer type 7 (HNPCC7). Several alternatively spliced transcript variants have been identified, but the full-length nature of only two transcript variants has been determined. [provided by RefSeq, Jul 2008]

MLH3 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -4 ACMG points.

BS2

High AC in GnomAd at 5 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MLH3	NM_001040108.2 linkuse as main transcript	c.124G>A	p.Ala42Thr	missense_variant	2/13	ENST00000355774.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MLH3	ENST00000355774.7 linkuse as main transcript	c.124G>A	p.Ala42Thr	missense_variant	2/13	5	NM_001040108.2	P1	Q9UHC1-1

Frequencies

GnomAD3 genomes

AF:

0.0000328

AC:

AN:

152218

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:

0.0000735

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000239

AC:

AN:

251442

Hom.:

AF XY:

0.0000221

AC XY:

AN XY:

135910

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:

0.0000528

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000499

AC:

AN:

1461890

Hom.:

Cov.:

AF XY:

0.0000385

AC XY:

AN XY:

727244

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000224

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:

0.0000647

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000328

AC:

AN:

152218

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74378

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:

0.0000735

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000752

Hom.:

Bravo

AF:

0.0000302

TwinsUK

AF:

0.00

AC:

ALSPAC

AF:

0.000259

AC:

ExAC

AF:

0.00000824

AC:

EpiCase

AF:

0.00

EpiControl

AF:

0.000178

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Colorectal cancer, hereditary nonpolyposis, type 7

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Invitae	Nov 17, 2023	This sequence change replaces alanine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 42 of the MLH3 protein (p.Ala42Thr). This variant is present in population databases (rs748676497, gnomAD 0.006%). This variant has not been reported in the literature in individuals affected with MLH3-related conditions. ClinVar contains an entry for this variant (Variation ID: 238242). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. 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. -
Uncertain significance, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	Jan 13, 2018	This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

not specified

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Oct 15, 2023

The p.A42T variant (also known as c.124G>A), located in coding exon 1 of the MLH3 gene, results from a G to A substitution at nucleotide position 124. The alanine at codon 42 is replaced by threonine, an amino acid with similar properties. This amino acid position is well conserved in available vertebrate species. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.47

BayesDel_addAF

Benign

-0.13

BayesDel_noAF

Benign

-0.27

Cadd

Uncertain

Dann

Uncertain

1.0

DEOGEN2

Benign

0.33

T;.;.;T;.;.

Eigen

Uncertain

0.62

Eigen_PC

Pathogenic

0.67

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Uncertain

0.93

D;D;D;.;D;D

M_CAP

Benign

0.021

MetaRNN

Uncertain

0.46

T;T;T;T;T;T

MetaSVM

Benign

-0.80

MutationAssessor

Benign

0.32

N;N;.;N;.;.

MutationTaster

Benign

1.0

D;D;D;D;D

PrimateAI

Uncertain

0.55

PROVEAN

Uncertain

-2.5

D;.;N;D;D;D

REVEL

Uncertain

0.32

Sift

Benign

0.060

T;.;D;T;T;T

Sift4G

Uncertain

0.011

D;D;D;D;.;.

Polyphen

1.0

D;D;.;D;.;.

Vest4

0.41

MutPred

0.45

Gain of catalytic residue at V43 (P = 0.0057);Gain of catalytic residue at V43 (P = 0.0057);Gain of catalytic residue at V43 (P = 0.0057);Gain of catalytic residue at V43 (P = 0.0057);Gain of catalytic residue at V43 (P = 0.0057);Gain of catalytic residue at V43 (P = 0.0057);

MVP

0.68

MPC

0.42

ClinPred

0.72

GERP RS

5.2

Varity_R

0.36

gMVP

0.47

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