14-75032143-C-T

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 0P and 2B. BP4BS1_Supporting

The NM_001040108.2(MLH3):c.3752G>A(p.Arg1251Gln) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000152 in 1,613,660 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 Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R1251W) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.00014 ( 0 hom., cov: 32)

Exomes 𝑓: 0.00015 ( 0 hom. )

Consequence

MLH3
NM_001040108.2 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:4

Conservation

PhyloP100: 2.29

Publications

1 publications found

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 Gene-Disease associations (from GenCC):

colorectal cancer, hereditary nonpolyposis, type 7
Inheritance: AD, AR Classification: MODERATE, LIMITED Submitted by: Ambry Genetics, ClinGen, Laboratory for Molecular Medicine

MLH3 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -2 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.27258447).

BS1

Variant frequency is greater than expected in population nfe. GnomAd4 allele frequency = 0.000138 (21/152158) while in subpopulation NFE AF = 0.000265 (18/68004). AF 95% confidence interval is 0.000171. There are 0 homozygotes in GnomAd4. There are 9 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MLH3	NM_001040108.2 link	c.3752G>A	p.Arg1251Gln	missense_variant	Exon 8 of 13	ENST00000355774.7	NP_001035197.1	Q9UHC1-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MLH3	ENST00000355774.7 link	c.3752G>A	p.Arg1251Gln	missense_variant	Exon 8 of 13	5	NM_001040108.2	ENSP00000348020.2		Q9UHC1-1

Frequencies

GnomAD3 genomes

AF:

0.000138

AC:

AN:

152040

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000242

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:

0.0000945

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.000265

Gnomad OTH

AF:

0.000478

GnomAD2 exomes

AF:

0.0000915

AC:

AN:

251438

AF XY:

0.0000809

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 FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000158

Gnomad OTH exome

AF:

0.000326

GnomAD4 exome

AF:

0.000154

AC:

225

AN:

1461502

Hom.:

Cov.:

AF XY:

0.000172

AC XY:

125

AN XY:

727094

show subpopulations

African (AFR)

AF:

0.0000299

AC:

AN:

33464

American (AMR)

AF:

0.00

AC:

AN:

44722

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26132

East Asian (EAS)

AF:

0.0000252

AC:

AN:

39692

South Asian (SAS)

AF:

0.0000464

AC:

AN:

86250

European-Finnish (FIN)

AF:

0.0000374

AC:

AN:

53408

Middle Eastern (MID)

AF:

0.000173

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.000184

AC:

204

AN:

1111686

Other (OTH)

AF:

0.000199

AC:

AN:

60380

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.455

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.000138

AC:

AN:

152158

Hom.:

Cov.:

AF XY:

0.000121

AC XY:

AN XY:

74388

show subpopulations

African (AFR)

AF:

0.0000241

AC:

AN:

41506

American (AMR)

AF:

0.00

AC:

AN:

15278

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5178

South Asian (SAS)

AF:

0.00

AC:

AN:

4820

European-Finnish (FIN)

AF:

0.0000945

AC:

AN:

10578

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.000265

AC:

AN:

68004

Other (OTH)

AF:

0.000473

AC:

AN:

2116

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.487

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.0000961

Hom.:

Bravo

AF:

0.000110

TwinsUK

AF:

0.00

AC:

ALSPAC

AF:

0.000778

AC:

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000116

AC:

ExAC

AF:

0.000107

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.000296

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not specified

Uncertain:2

Mar 04, 2025

Center for Genomic Medicine, Rigshospitalet, Copenhagen University Hospital

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Sep 22, 2024

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The p.R1251Q variant (also known as c.3752G>A), located in coding exon 7 of the MLH3 gene, results from a G to A substitution at nucleotide position 3752. The arginine at codon 1251 is replaced by glutamine, an amino acid with highly similar properties. This amino acid position is well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Colorectal cancer, hereditary nonpolyposis, type 7

Uncertain:2

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

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. -

Jan 22, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces arginine, which is basic and polar, with glutamine, which is neutral and polar, at codon 1251 of the MLH3 protein (p.Arg1251Gln). This variant is present in population databases (rs201721635, gnomAD 0.02%). 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: 410897). 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. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.098

BayesDel_addAF

Benign

-0.15

BayesDel_noAF

Benign

-0.15

CADD

Uncertain

(source)

DANN

Pathogenic

1.0

DEOGEN2

Benign

0.079

T;.;T

Eigen

Uncertain

0.57

Eigen_PC

Uncertain

0.59

FATHMM_MKL

Uncertain

0.79

LIST_S2

Uncertain

0.91

D;D;.

M_CAP

Uncertain

0.12

MetaRNN

Benign

0.27

T;T;T

MetaSVM

Uncertain

0.015

MutationAssessor

Benign

1.8

L;.;L

PhyloP100

2.3

PrimateAI

Benign

0.31

PROVEAN

Benign

-1.7

N;.;N

REVEL

Uncertain

0.36

Sift

Benign

0.052

T;.;T

Sift4G

Uncertain

0.023

D;D;D

Polyphen

0.99

D;D;D

Vest4

0.28

MVP

0.89

MPC

0.53

ClinPred

0.23

GERP RS

5.0

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.24

gMVP

0.20

Mutation Taster

=91/9

polymorphism

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over