rs1060500708

Positions:

• chr3-37028844-G-A
• chr3-37028844-G-C
• chr3-37028844-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 2P and 1B. PM2 BP4

The NM_000249.4(MLH1):​c.1470G>A​(p.Met490Ile) 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 (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: MLH1 NM_000249.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 5.97

Genes affected

MLH1 (HGNC:7127): (mutL homolog 1) The protein encoded by this gene can heterodimerize with mismatch repair endonuclease PMS2 to form MutL alpha, part of the DNA mismatch repair system. When MutL alpha is bound by MutS beta and some accessory proteins, the PMS2 subunit of MutL alpha introduces a single-strand break near DNA mismatches, providing an entry point for exonuclease degradation. The encoded protein is also involved in DNA damage signaling and can heterodimerize with DNA mismatch repair protein MLH3 to form MutL gamma, which is involved in meiosis. This gene was identified as a locus frequently mutated in hereditary nonpolyposis colon cancer (HNPCC). [provided by RefSeq, Aug 2017]

ACMG classification

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=0.33690482).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MLH1	NM_000249.4	c.1470G>A	p.Met490Ile	missense_variant	13/19	ENST00000231790.8	NP_000240.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MLH1	ENST00000231790.8	c.1470G>A	p.Met490Ile	missense_variant	13/19	1	NM_000249.4	ENSP00000231790	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hereditary nonpolyposis colorectal neoplasms Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Oct 26, 2019

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. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has not been reported in the literature in individuals with MLH1-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces methionine with isoleucine at codon 490 of the MLH1 protein (p.Met490Ile). The methionine residue is weakly conserved and there is a small physicochemical difference between methionine and isoleucine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.25
BayesDel_addAF	Pathogenic	0.22	D
BayesDel_noAF	Uncertain	0.080
CADD	Benign	23
DANN	Uncertain	0.99
DEOGEN2	Benign	0.29	T;.;.;.;.;.;T;T
Eigen	Benign	0.0061
Eigen_PC	Uncertain	0.25
FATHMM_MKL	Uncertain	0.94	D
LIST_S2	Benign	0.72	T;T;.;.;.;T;T;T
M_CAP	Benign	0.060	D
MetaRNN	Benign	0.34	T;T;T;T;T;T;T;T
MetaSVM	Uncertain	-0.094	T
MutationAssessor	Benign	1.9	M;.;.;.;.;.;.;.
MutationTaster	Benign	1.0	D;D;D;D;D;D
PrimateAI	Uncertain	0.53	T
PROVEAN	Benign	-0.70	N;N;N;N;N;N;D;N
REVEL	Uncertain	0.32
Sift	Benign	0.34	T;T;T;T;T;T;D;T
Sift4G	Benign	0.47	T;T;T;T;T;T;D;D
Polyphen		0.0	B;.;.;.;.;.;.;.
Vest4		0.53
MutPred		0.31		Loss of catalytic residue at M490 (P = 0.004);.;.;.;.;.;.;.;
MVP		0.90
MPC		0.073
ClinPred		0.87	D
GERP RS		6.0
Varity_R		0.096
gMVP		0.20

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

Other links and lift over

dbSNP: rs1060500708; hg19: chr3-37070335;