14-75048921-G-C

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PVS1PM2

The NM_001040108.2(MLH3):c.735C>G(p.Tyr245*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000274 in 1,461,076 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 (★). Synonymous variant affecting the same amino acid position (i.e. Y245Y) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 0.0000027 ( 0 hom. )

Consequence

MLH3
NM_001040108.2 stop_gained

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 2.00

Publications

0 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: Pathogenic. The variant received 10 ACMG points.

PVS1

Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.

PM2

Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MLH3	NM_001040108.2 link	c.735C>G	p.Tyr245*	stop_gained	Exon 2 of 13	ENST00000355774.7	NP_001035197.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein
MLH3	ENST00000355774.7 link	c.735C>G	p.Tyr245*	stop_gained	Exon 2 of 13	5	NM_001040108.2	ENSP00000348020.2
MLH3	ENST00000380968.6 link	c.735C>G	p.Tyr245*	stop_gained	Exon 2 of 12	1		ENSP00000370355.3
MLH3	ENST00000556257.5 link	c.735C>G	p.Tyr245*	stop_gained	Exon 2 of 7	5		ENSP00000451540.1
MLH3	ENST00000553263.1 link	c.*248C>G		downstream_gene_variant		2		ENSP00000451192.1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

0.00000274

AC:

AN:

1461076

Hom.:

Cov.:

AF XY:

0.00000550

AC XY:

AN XY:

726772

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33406

American (AMR)

AF:

0.00

AC:

AN:

44604

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26116

East Asian (EAS)

AF:

0.00

AC:

AN:

39690

South Asian (SAS)

AF:

0.00

AC:

AN:

86122

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53406

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5764

European-Non Finnish (NFE)

AF:

0.00000360

AC:

AN:

1111612

Other (OTH)

AF:

0.00

AC:

AN:

60356

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.425

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

Cov.:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Jun 06, 2025

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The p.Y245* variant (also known as c.735C>G), located in coding exon 1 of the MLH3 gene, results from a C to G substitution at nucleotide position 735. This changes the amino acid from a tyrosine to a stop codon within coding exon 1. This alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. However, the evidence for this gene-disease relationship is limited; therefore, the clinical significance of this alteration is unclear.

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.63

BayesDel_noAF

Pathogenic

0.57

CADD

Pathogenic

(source)

DANN

Uncertain

0.99

DEOGEN2

Benign

0.0

.;.;.;.

Eigen

Uncertain

0.30

Eigen_PC

Benign

0.10

FATHMM_MKL

Uncertain

0.95

LIST_S2

Benign

0.0

.;.;.;.

MetaRNN

Benign

0.0

.;.;.;.

MutationAssessor

Benign

0.0

.;.;.;.

PhyloP100

2.0

PROVEAN

Benign

0.0

.;.;.;.

REVEL

Benign

0.0

Sift

Pathogenic

0.0

.;.;.;.

Sift4G

Pathogenic

0.0

.;.;.;.

Vest4

0.83

GERP RS

-1.3

Mutation Taster

=3/197

disease causing (fs/PTC)

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over