14-75048990-C-G

Position:

chr14-75048990-C-G

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 2P and 1B. PM2BP4

The NM_001040108.2(MLH3):c.666G>C(p.Lys222Asn) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000031 in 1,613,908 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 (★★). Synonymous variant affecting the same amino acid position (i.e. K222K) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 33)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

MLH3
NM_001040108.2 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:2

Conservation

PhyloP100: 0.967

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 Uncertain_significance. Variant got 1 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.40783483).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MLH3	NM_001040108.2 linkuse as main transcript	c.666G>C	p.Lys222Asn	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.666G>C	p.Lys222Asn	missense_variant	2/13	5	NM_001040108.2	P1	Q9UHC1-1
MLH3	ENST00000380968.6 linkuse as main transcript	c.666G>C	p.Lys222Asn	missense_variant	2/12	1			Q9UHC1-2
MLH3	ENST00000556257.5 linkuse as main transcript	c.666G>C	p.Lys222Asn	missense_variant	2/7	5

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

152174

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000196

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:

0.000478

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461734

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

727140

show subpopulations

Gnomad4 AFR exome

AF:

0.00

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:

8.99e-7

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000263

AC:

AN:

152174

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74332

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.000196

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:

0.000478

Bravo

AF:

0.0000642

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Dec 03, 2022

The p.K222N variant (also known as c.666G>C), located in coding exon 1 of the MLH3 gene, results from a G to C substitution at nucleotide position 666. The lysine at codon 222 is replaced by asparagine, an amino acid with similar properties. This alteration was identified in 1/1358 non-cancer control individuals and in 0/57 cases, in a study looking at cancer predisposition mutations in patients with cutaneous melanoma and a history of at least two additional non-cutaneous melanoma primary cancers (Pritchard AL et al. PLoS One, 2018 Apr;13:e0194098). 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. -

Colorectal cancer, hereditary nonpolyposis, type 7

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jan 11, 2024

This sequence change replaces lysine, which is basic and polar, with asparagine, which is neutral and polar, at codon 222 of the MLH3 protein (p.Lys222Asn). This variant is not present in population databases (gnomAD no frequency). 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: 1754792). 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

Uncertain

0.56

BayesDel_addAF

Benign

-0.064

BayesDel_noAF

Benign

-0.33

CADD

Benign

DANN

Uncertain

1.0

DEOGEN2

Uncertain

0.46

T;.;.;T

Eigen

Uncertain

0.32

Eigen_PC

Uncertain

0.29

FATHMM_MKL

Uncertain

0.92

LIST_S2

Benign

0.85

D;T;T;.

M_CAP

Benign

0.048

MetaRNN

Benign

0.41

T;T;T;T

MetaSVM

Uncertain

0.17

MutationAssessor

Benign

1.9

L;L;.;L

MutationTaster

Benign

0.043

P;P;P;P;P

PrimateAI

Uncertain

0.72

PROVEAN

Uncertain

-3.0

D;.;D;D

REVEL

Uncertain

0.47

Sift

Benign

0.031

D;.;D;D

Sift4G

Uncertain

0.018

D;D;D;D

Polyphen

0.97

D;D;.;D

Vest4

0.16

MutPred

0.45

Gain of catalytic residue at L223 (P = 0.0056);Gain of catalytic residue at L223 (P = 0.0056);Gain of catalytic residue at L223 (P = 0.0056);Gain of catalytic residue at L223 (P = 0.0056);

MVP

0.88

MPC

0.34

ClinPred

0.98

GERP RS

3.8

Varity_R

0.58

gMVP

0.53

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