rs781637991
Variant summary
Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM1PM2
The NM_000249.4(MLH1):c.2024G>A(p.Ser675Asn) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. S675I) has been classified as Uncertain significance.
Frequency
Genomes: not found (cov: 32)
Consequence
MLH1
NM_000249.4 missense
NM_000249.4 missense
Scores
10
9
Clinical Significance
Conservation
PhyloP100: 2.88
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]
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ACMG classification
Classification made for transcript
Verdict is Uncertain_significance. Variant got 4 ACMG points.
PM1
In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 16 uncertain in NM_000249.4
PM2
Very rare variant in population databases, with high coverage;
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | MANE | UniProt |
---|---|---|---|---|---|---|---|
MLH1 | NM_000249.4 | c.2024G>A | p.Ser675Asn | missense_variant | 18/19 | ENST00000231790.8 |
Ensembl
Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | TSL | MANE | Appris | UniProt |
---|---|---|---|---|---|---|---|---|---|
MLH1 | ENST00000231790.8 | c.2024G>A | p.Ser675Asn | missense_variant | 18/19 | 1 | NM_000249.4 | P1 |
Frequencies
GnomAD3 genomes Cov.: 32
GnomAD3 genomes
Cov.:
32
GnomAD3 exomes AF: 0.00000398 AC: 1AN: 251272Hom.: 0 AF XY: 0.00000736 AC XY: 1AN XY: 135786
GnomAD3 exomes
AF:
AC:
1
AN:
251272
Hom.:
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AC XY:
1
AN XY:
135786
Gnomad AFR exome
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GnomAD4 exome Cov.: 31
GnomAD4 exome
Cov.:
31
GnomAD4 genome Cov.: 32
GnomAD4 genome
Cov.:
32
ExAC
AF:
AC:
1
ClinVar
Significance: Uncertain significance
Submissions summary: Uncertain:4
Revision: criteria provided, multiple submitters, no conflicts
LINK: link
Submissions by phenotype
Colorectal cancer, hereditary nonpolyposis, type 2 Uncertain:1
Uncertain significance, criteria provided, single submitter | clinical testing | Baylor Genetics | Feb 19, 2024 | - - |
not provided Uncertain:1
Uncertain significance, criteria provided, single submitter | clinical testing | GeneDx | Oct 15, 2015 | This variant is denoted MLH1 c.2024G>A at the cDNA level and p.Ser675Asn (S675N) at the protein level, and results in the change of a Serine to an Asparagine (AGC>AAC). This variant has not, to our knowledge, been published in the literature as pathogenic or benign. This variant was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, suggesting it is not a common benign variant in these populations. Since Serine and Asparagine share similar properties, this is considered a conservative amino acid substitution. MLH1 Ser675Asn occurs at a position that is conserved in mammals and is located in a region that is required for interaction with PMS2, MLH3 and PMS1 (Pang 1997, Raevaara 2005). 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 Ser675Asn is a pathogenic or benign variant. We consider it to be a variant of uncertain significance. - |
Hereditary nonpolyposis colorectal neoplasms Uncertain:1
Uncertain significance, criteria provided, single submitter | clinical testing | Invitae | Apr 28, 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. 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) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on MLH1 protein function. ClinVar contains an entry for this variant (Variation ID: 234563). This variant has not been reported in the literature in individuals affected with MLH1-related conditions. This variant is present in population databases (rs781637991, gnomAD 0.006%). This sequence change replaces serine, which is neutral and polar, with asparagine, which is neutral and polar, at codon 675 of the MLH1 protein (p.Ser675Asn). - |
Hereditary cancer-predisposing syndrome Uncertain:1
Uncertain significance, criteria provided, single submitter | clinical testing | Color Diagnostics, LLC DBA Color Health | Feb 09, 2019 | - - |
Computational scores
Source:
Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
BayesDel_addAF
Uncertain
T
BayesDel_noAF
Uncertain
CADD
Benign
DANN
Uncertain
DEOGEN2
Uncertain
D;.;.;.;.;.
Eigen
Benign
Eigen_PC
Uncertain
FATHMM_MKL
Uncertain
D
LIST_S2
Benign
T;T;.;.;.;T
M_CAP
Benign
D
MetaRNN
Uncertain
T;T;T;T;T;T
MetaSVM
Uncertain
D
MutationAssessor
Benign
L;.;.;.;.;.
MutationTaster
Benign
D;D;D;D;D;D
PrimateAI
Uncertain
T
PROVEAN
Benign
N;N;N;N;N;N
REVEL
Uncertain
Sift
Benign
T;T;T;T;T;T
Sift4G
Benign
T;T;T;T;T;T
Polyphen
B;.;.;.;.;.
Vest4
MutPred
Loss of phosphorylation at S675 (P = 0.0594);.;.;.;.;.;
MVP
MPC
ClinPred
T
GERP RS
Varity_R
gMVP
Splicing
Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
Details are displayed if max score is > 0.2
Find out detailed SpliceAI scores and Pangolin per-transcript scores at