3-37028824-G-T

Position:

• chr3-37028824-G-T

Variant summary

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

The NM_000249.4(MLH1):​c.1450G>T​(p.Asp484Tyr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,218 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 (★★).

• Frequency: Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
• Consequence: MLH1 NM_000249.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 2.65

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]

MLH1 (HGNC:):

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=0.26166365).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MLH1	NM_000249.4	c.1450G>T	p.Asp484Tyr	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.1450G>T	p.Asp484Tyr	missense_variant	13/19	1	NM_000249.4	ENSP00000231790.3

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152218 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.000207

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome Cov.: 32

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152218 Hom.: 0 Cov.: 32 AF XY: 0.0000134 AC XY: 1 AN XY: 74374

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.000207

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Jul 22, 2014

This variant is denoted MLH1 c.1450G>T at the cDNA level, p.Asp484Tyr (D484Y) at the protein level, and results in the change of an Aspartic Acid to a Tyrosine (GAT>TAT). This variant has not, to our knowledge, been published in the literature as pathogenic or benign. MLH1 Asp484Tyr was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. Since Aspartic Acid and Tyrosine differ in polarity, charge, size or other properties, this is considered a non-conservative amino acid substitution. MLH1 Asp484Tyr occurs at a position that is variable across species and is located in within the EXO1 interaction region (UniProt). In silico analyses are inconsistent regarding the effect this variant may have on protein structure and function. Based on currently available information, it is unclear whether MLH1 Asp484Tyr is pathogenic or benign. We consider it to be a variant of uncertain significance. -

Hereditary nonpolyposis colorectal neoplasms Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Dec 20, 2022

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. 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. ClinVar contains an entry for this variant (Variation ID: 182525). This variant has not been reported in the literature in individuals affected with MLH1-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces aspartic acid, which is acidic and polar, with tyrosine, which is neutral and polar, at codon 484 of the MLH1 protein (p.Asp484Tyr). -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Apr 28, 2021

The p.D484Y variant (also known as c.1450G>T), located in coding exon 13 of the MLH1 gene, results from a G to T substitution at nucleotide position 1450. The aspartic acid at codon 484 is replaced by tyrosine, an amino acid with highly dissimilar properties. This amino acid position is not well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.098
BayesDel_addAF	Pathogenic	0.19	D
BayesDel_noAF	Uncertain	0.040
CADD	Benign	23
DANN	Uncertain	0.99
DEOGEN2	Benign	0.40	T;.;.;.;.;.;T;T
Eigen	Benign	-0.041
Eigen_PC	Benign	-0.033
FATHMM_MKL	Uncertain	0.88	D
LIST_S2	Uncertain	0.90	D;D;.;.;.;D;D;D
M_CAP	Benign	0.047	D
MetaRNN	Benign	0.26	T;T;T;T;T;T;T;T
MetaSVM	Benign	-0.77	T
MutationAssessor	Uncertain	2.1	M;.;.;.;.;.;.;.
PrimateAI	Benign	0.41	T
PROVEAN	Benign	-1.8	N;N;N;N;N;N;D;D
REVEL	Uncertain	0.54
Sift	Uncertain	0.0050	D;D;D;D;D;D;D;D
Sift4G	Benign	0.16	T;D;D;D;D;D;D;D
Polyphen		0.15	B;.;.;.;.;.;.;.
Vest4		0.57
MutPred		0.32		Loss of sheet (P = 0.0011);.;.;.;.;.;.;.;
MVP		0.92
MPC		0.15
ClinPred		0.68	D
GERP RS		2.9
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		2.2
Varity_R		0.13
gMVP		0.50

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: rs730881741; hg19: chr3-37070315; COSMIC: COSV105856765; COSMIC: COSV105856765;