rs587780681

Positions:

• chr3-37048943-A-G
• chr3-37048943-A-T

Variant summary

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

The NM_000249.4(MLH1):​c.2029A>G​(p.Ser677Gly) variant causes a missense change. The variant allele was found at a frequency of 0.0000131 in 152,222 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency: Genomes: 𝑓 0.000013 (0 hom., cov: 32)
• Consequence: MLH1 NM_000249.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 5.71

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 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MLH1	NM_000249.4	c.2029A>G	p.Ser677Gly	missense_variant	18/19	ENST00000231790.8	NP_000240.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MLH1	ENST00000231790.8	c.2029A>G	p.Ser677Gly	missense_variant	18/19	1	NM_000249.4	ENSP00000231790.3

Frequencies

GnomAD3 genomes AF: 0.0000131 AC: 2 AN: 152222 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: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000294

Gnomad OTH AF: 0.00

GnomAD4 exome Cov.: 31

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152222 Hom.: 0 Cov.: 32 AF XY: 0.0000269 AC XY: 2 AN XY: 74366

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000294

Gnomad4 OTH AF: 0.00

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hereditary nonpolyposis colorectal neoplasms Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Apr 15, 2023

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 output the following: SIFT: "Not Available"; PolyPhen-2: "Benign"; Align-GVGD: "Not Available". The glycine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. ClinVar contains an entry for this variant (Variation ID: 1784706). This variant has not been reported in the literature in individuals affected with MLH1-related conditions. This variant is present in population databases (no rsID available, gnomAD 0.007%). This sequence change replaces serine, which is neutral and polar, with glycine, which is neutral and non-polar, at codon 677 of the MLH1 protein (p.Ser677Gly). -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Apr 06, 2023

The p.S677G variant (also known as c.2029A>G), located in coding exon 18 of the MLH1 gene, results from an A to G substitution at nucleotide position 2029. The serine at codon 677 is replaced by glycine, an amino acid with similar properties. This amino acid position is well conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. 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	0.10
BayesDel_addAF	Pathogenic	0.28	D
BayesDel_noAF	Pathogenic	0.16
CADD	Benign	23
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.82	D;.;.;.;.;.
Eigen	Uncertain	0.39
Eigen_PC	Uncertain	0.42
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Benign	0.74	T;T;.;.;.;T
M_CAP	Uncertain	0.20	D
MetaRNN	Uncertain	0.50	D;D;D;D;D;D
MetaSVM	Uncertain	0.48	D
MutationAssessor	Uncertain	2.4	M;.;.;.;.;.
PrimateAI	Uncertain	0.59	T
PROVEAN	Benign	-2.0	N;N;N;N;N;N
REVEL	Uncertain	0.63
Sift	Benign	0.059	T;T;T;T;T;T
Sift4G	Uncertain	0.053	T;T;T;T;T;T
Polyphen		0.93	P;.;.;.;.;.
Vest4		0.47
MutPred		0.49		Loss of ubiquitination at K678 (P = 0.0709);.;.;.;.;.;
MVP		0.93
MPC		0.062
ClinPred		0.87	D
GERP RS		4.8
Varity_R		0.66
gMVP		0.73

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs587780681; hg19: chr3-37090434;