NM_000251.3:c.581T>C
Variant summary
Our verdict is Uncertain significance. Variant got 1 ACMG points: 2P and 1B. PM1BP6
The NM_000251.3(MSH2):āc.581T>Cā(p.Ile194Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000105 in 1,613,984 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).
Frequency
Consequence
NM_000251.3 missense
Scores
Clinical Significance
Conservation
Genome browser will be placed here
ACMG classification
Verdict is Uncertain_significance. Variant got 1 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000197 AC: 3AN: 152104Hom.: 0 Cov.: 31
GnomAD3 exomes AF: 0.00000398 AC: 1AN: 251420Hom.: 0 AF XY: 0.00 AC XY: 0AN XY: 135894
GnomAD4 exome AF: 0.00000958 AC: 14AN: 1461880Hom.: 0 Cov.: 32 AF XY: 0.00000688 AC XY: 5AN XY: 727242
GnomAD4 genome AF: 0.0000197 AC: 3AN: 152104Hom.: 0 Cov.: 31 AF XY: 0.0000135 AC XY: 1AN XY: 74304
ClinVar
Submissions by phenotype
not provided Uncertain:3
- -
- -
This variant is denoted MSH2 c.581T>C at the cDNA level, p.Ile194Thr (I194T) at the protein level, and results in the change of an Isoleucine to a Threonine (ATT>ACT). In a yeast based functional assay, MSH2 Ile194Thr was not shown to cause any mismatch repair defects (Martinez 2010). MSH2 Ile194Thr 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 Isoleucine and Threonine differ in polarity, charge, size or other properties, this is considered a non-conservative amino acid substitution. MSH2 Ile194Thr occurs at a position that is well conserved across species and is located in the connector domain (Lutzen 2008). 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 MSH2 Ile194Thr is pathogenic or benign. We consider it to be a variant of uncertain significance. -
Lynch syndrome Uncertain:2
The MSH2 p.Ile194Thr variant was identified in the literature in functional analysis of human mismatch repair gene mutations using S. cerevisiae-based assay and had no significant difference between mutation and wild-type rates (Martinez 2010). The variant was also identified in dbSNP (ID: rs730881778) as "With Uncertain significance allele", and in ClinVar (classified as uncertain significance by Invitae, GeneDx and Ambry Genetics). The variant was not identified in UMD-LSDB. The variant was identified in control databases in 1 of 246194 chromosomes at a frequency of 0.000004 (Genome Aggregation Database Feb 27, 2017). The variant was observed in the European population in 1 of 111648 chromosomes (freq: 0.000009), while the variant was not observed in the African, Other, Latino, Ashkenazi Jewish, East Asian, Finnish, and South Asian populations. The p.Ile194 residue is conserved in mammals and computational analyses (PolyPhen-2, SIFT, AlignGVGD, BLOSUM, MutationTaster) provide inconsistent predictions regarding the impact to the protein; this information is not very predictive of pathogenicity. The variant occurs outside of the splicing consensus sequence and in silico or computational prediction software programs (SpliceSiteFinder, MaxEntScan, NNSPLICE, GeneSplicer) do not predict a difference in splicing. In summary, based on the above information the clinical significance of this variant cannot be determined with certainty at this time. This variant is classified as a variant of uncertain significance. -
This missense variant replaces isoleucine with threonine at codon 194 of the MSH2 protein. Computational prediction suggests that this variant may have deleterious impact on protein structure and function (internally defined REVEL score threshold >= 0.7, PMID: 27666373). This variant does not impact MSH2 function in a 6-thioguanine sensitivity assay in haploid human cells (internally defined LOF score threshold <= -1.32, PMID: 33357406), and retained wild type MSH2 mismatch repair activity in yeast (PMID: 20176959). This variant has been reported in an individual affected with hereditary breast or ovarian cancer (PMID: 30262796). This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). 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. -
Hereditary cancer-predisposing syndrome Uncertain:1Benign:1
This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -
This missense variant replaces isoleucine with threonine at codon 194 of the MSH2 protein. Computational prediction suggests that this variant may have deleterious impact on protein structure and function (internally defined REVEL score threshold >= 0.7, PMID: 27666373). This variant does not impact MSH2 function in a 6-thioguanine sensitivity assay in haploid human cells (internally defined LOF score threshold <= -1.32, PMID: 33357406), and retained wild type MSH2 mismatch repair activity in yeast (PMID: 20176959). This variant has been reported in an individual affected with hereditary breast or ovarian cancer (PMID: 30262796). This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). 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. -
Lynch syndrome 1 Uncertain:1
- -
Hereditary nonpolyposis colorectal neoplasms Benign:1
- -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at