rs886037843
Variant summary
Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM2PP3_ModeratePP5
The NM_007215.4(POLG2):c.544C>T(p.Arg182Trp) variant causes a missense change. The variant allele was found at a frequency of 0.00000379 in 1,581,626 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).
Frequency
Consequence
NM_007215.4 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Uncertain_significance. Variant got 5 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000131 AC: 2AN: 152178Hom.: 0 Cov.: 32
GnomAD4 exome AF: 0.00000280 AC: 4AN: 1429330Hom.: 0 Cov.: 30 AF XY: 0.00000567 AC XY: 4AN XY: 705612
GnomAD4 genome AF: 0.0000131 AC: 2AN: 152296Hom.: 0 Cov.: 32 AF XY: 0.0000269 AC XY: 2AN XY: 74478
ClinVar
Submissions by phenotype
not provided Pathogenic:1Uncertain:1
The R182W variant in the POLG2 gene has been reported in the homozygous state in an individual with infantile fulminant liver failure and mitochondrial depletion in liver and muscle. This individual's heterozygous parents were reportedly unaffected (Varma et al., 2016). The R182W variant was not observed in approximately 6500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. The R182W variant is a non-conservative amino acid substitution, which is likely to impact secondary protein structure as these residues differ in polarity, charge, size and/or other properties. This substitution occurs at a position that is conserved across species and in silico analysis predicts this variant is probably damaging to the protein structure/function. Therefore, we interpret R182W as a likely pathogenic variant, however the possibility it may be a rare benign variant cannot be excluded. -
This sequence change replaces arginine, which is basic and polar, with tryptophan, which is neutral and slightly polar, at codon 182 of the POLG2 protein (p.Arg182Trp). This variant is present in population databases (no rsID available, gnomAD 0.007%). This missense change has been observed in individual(s) with POLG2-related conditions (PMID: 27592148). ClinVar contains an entry for this variant (Variation ID: 252958). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. Experimental studies have shown that this missense change affects POLG2 function (PMID: 30157269). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. 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. -
Acute liver failure Pathogenic:1
Parents are heterozygous and phenotypically normal. The patient is homozygous and has severe mtDNA depeletion. POLG2 encodes the accessory subunit of DNA polymerase and is involved in mtDNA replication. -
Mitochondrial DNA depletion syndrome 16A Pathogenic:1
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Progressive external ophthalmoplegia with mitochondrial DNA deletions, autosomal dominant 4 Uncertain:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at