3-37025698-C-A

Position:

• chr3-37025698-C-A

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_000249.4(MLH1):​c.1100C>A​(p.Thr367Asn) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,362 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 30)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: MLH1 NM_000249.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:4
• Conservation: PhyloP100: 0.944

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 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.09496787).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MLH1	NM_000249.4	c.1100C>A	p.Thr367Asn	missense_variant	12/19	ENST00000231790.8	NP_000240.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MLH1	ENST00000231790.8	c.1100C>A	p.Thr367Asn	missense_variant	12/19	1	NM_000249.4	ENSP00000231790	P1

Frequencies

GnomAD3 genomes Cov.: 30

GnomAD3 exomes AF: 0.00000796 AC: 2 AN: 251288 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135864

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.000109

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461362 Hom.: 0 Cov.: 34 AF XY: 0.00 AC XY: 0 AN XY: 726986

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000504

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 30

Alfa AF: 0.0000434 Hom.: 0

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:3

Uncertain significance, criteria provided, single submitter	curation	Sema4, Sema4	Nov 30, 2021	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Sep 25, 2023	This missense variant replaces threonine with asparagine at codon 367 of the MLH1 protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in an individual affected with Lynch syndrome (PMID: 29237405). However, this individual also carried a large deletion variant that included the 3' end of EPCAM and exon 1 of MSH2 that could explain the observed phenotype. This variant has been identified in 2/251288 chromosomes in the general population by the Genome Aggregation Database (gnomAD) and has been reported in the Chinese general population (PMID: 34172528). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -
Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Dec 29, 2022	The p.T367N variant (also known as c.1100C>A), located in coding exon 12 of the MLH1 gene, results from a C to A substitution at nucleotide position 1100. The threonine at codon 367 is replaced by asparagine, an amino acid with similar properties. This alteration was identified in an Asian individual who had sigmoid cancer at age 33 whose father and paternal grandmother both had colon cancer diagnosed before the age of 40; however, this individual also had a co-occurring 3'EPCAM/MSH2 exon 1 deletion that was likely the cause of disease in this family, although mismatch repair immunohistochemistry was not done on this tumor (Lee J et al. BMC Cancer, 2017 12;17:843). This amino acid position is not 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. -

Hereditary nonpolyposis colorectal neoplasms Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 28, 2024

This sequence change replaces threonine, which is neutral and polar, with asparagine, which is neutral and polar, at codon 367 of the MLH1 protein (p.Thr367Asn). This variant is present in population databases (rs776402584, gnomAD 0.006%). This missense change has been observed in individual(s) with colon cancer (PMID: 29237405). ClinVar contains an entry for this variant (Variation ID: 629890). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt MLH1 protein function with a negative predictive value of 95%. 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	0.080
BayesDel_addAF	Benign	-0.084	T
BayesDel_noAF	Benign	-0.19
CADD	Benign	3.3
DANN	Benign	0.80
DEOGEN2	Benign	0.31	T;.;.;.;.;.
Eigen	Benign	-1.2
Eigen_PC	Benign	-1.2
FATHMM_MKL	Benign	0.31	N
LIST_S2	Benign	0.65	T;T;.;.;.;T
M_CAP	Benign	0.070	D
MetaRNN	Benign	0.095	T;T;T;T;T;T
MetaSVM	Benign	-0.67	T
MutationAssessor	Benign	1.4	L;.;.;.;.;.
MutationTaster	Benign	1.0	N;N;N;N;N;N
PrimateAI	Benign	0.34	T
PROVEAN	Benign	-0.40	N;N;N;N;N;N
REVEL	Uncertain	0.40
Sift	Benign	0.54	T;T;T;T;T;T
Sift4G	Benign	0.49	T;T;T;T;T;T
Polyphen		0.0	B;.;.;.;.;.
Vest4		0.28
MutPred		0.18		Loss of phosphorylation at T367 (P = 0.0165);.;.;.;.;.;
MVP		0.93
MPC		0.075
ClinPred		0.018	T
GERP RS		0.32
Varity_R		0.019
gMVP		0.13

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: rs776402584; hg19: chr3-37067189;