14-75047402-C-T

Variant names:

• chr14-75047402-C-T
• rs906500178
• NM_001040108.2:c.2254G>A

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 2P and 1B. PM2 BP4

The NM_001040108.2(MLH3):​c.2254G>A​(p.Gly752Arg) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. 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. G752V) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 33)
• Consequence: MLH3 NM_001040108.2 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 5.75
• Publications: 0 publications found

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

ACMG classification

Our verdict: Uncertain_significance. The variant received 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.3287823).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001040108.2. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MLH3	NM_001040108.2	MANE Select	c.2254G>A	p.Gly752Arg	missense	Exon 2 of 13	NP_001035197.1
	MLH3	NM_014381.3		c.2254G>A	p.Gly752Arg	missense	Exon 2 of 12	NP_055196.2

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MLH3	ENST00000355774.7	TSL:5 MANE Select	c.2254G>A	p.Gly752Arg	missense	Exon 2 of 13	ENSP00000348020.2
	MLH3	ENST00000380968.6	TSL:1	c.2254G>A	p.Gly752Arg	missense	Exon 2 of 12	ENSP00000370355.3
	MLH3	ENST00000556257.5	TSL:5	c.2254G>A	p.Gly752Arg	missense	Exon 2 of 7	ENSP00000451540.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 35

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Uncertain:1

Jun 09, 2025

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.G752R variant (also known as c.2254G>A), located in coding exon 1 of the MLH3 gene, results from a G to A substitution at nucleotide position 2254. The glycine at codon 752 is replaced by arginine, an amino acid with dissimilar 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. The evidence for this gene-disease relationship is limited; therefore, the clinical significance of this alteration is unclear.

Colorectal cancer, hereditary nonpolyposis, type 7 Uncertain:1

Jan 14, 2018

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). 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. This variant has not been reported in the literature in individuals with MLH3-related disease. This variant is not present in population databases (ExAC no frequency). This sequence change replaces glycine with arginine at codon 752 of the MLH3 protein (p.Gly752Arg). The glycine residue is moderately conserved and there is a moderate physicochemical difference between glycine and arginine.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.65
BayesDel_addAF	Benign	-0.035	T
BayesDel_noAF	Benign	-0.29
CADD	Uncertain	26
DANN	Uncertain	1.0
DEOGEN2	Benign	0.26	T
Eigen	Pathogenic	0.78
Eigen_PC	Pathogenic	0.78
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Uncertain	0.92	D
M_CAP	Benign	0.036	D
MetaRNN	Benign	0.33	T
MetaSVM	Benign	-0.81	T
MutationAssessor	Benign	1.5	L
PhyloP100		5.7
PrimateAI	Benign	0.47	T
PROVEAN	Uncertain	-3.0	D
REVEL	Benign	0.17
Sift	Uncertain	0.0020	D
Sift4G	Uncertain	0.0080	D
Polyphen		1.0	D
Vest4		0.38
MutPred		0.36		Loss of loop (P = 0.0073)
MVP		0.76
MPC		0.55
ClinPred		0.97	D
GERP RS		5.9
Varity_R		0.45
gMVP		0.67
Mutation Taster		=86/14	polymorphism

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

Other links and lift over

dbSNP: rs906500178; hg19: chr14-75514105;