rs139717885
Variant summary
Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PP3_StrongPP5_Very_Strong
The NM_002693.3(POLG):c.1789C>T(p.Arg597Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000143 in 1,613,526 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 Likely pathogenic (★★).
Frequency
Consequence
NM_002693.3 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Pathogenic. Variant got 12 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000131 AC: 2AN: 152186Hom.: 0 Cov.: 32
GnomAD3 exomes AF: 0.0000279 AC: 7AN: 250782Hom.: 0 AF XY: 0.0000221 AC XY: 3AN XY: 135660
GnomAD4 exome AF: 0.0000144 AC: 21AN: 1461222Hom.: 0 Cov.: 33 AF XY: 0.0000165 AC XY: 12AN XY: 726968
GnomAD4 genome AF: 0.0000131 AC: 2AN: 152304Hom.: 0 Cov.: 32 AF XY: 0.0000269 AC XY: 2AN XY: 74466
ClinVar
Submissions by phenotype
not provided Pathogenic:3
Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 19251978, 25356970, 27538604, 21880868, 20138553, 3346985, 35289132, 33486010, 32650990, 34927673, 34040194, 37184518) -
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Progressive sclerosing poliodystrophy Pathogenic:3
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The NM_002693.2:c.1789C>T (NP_002684.1:p.Arg597Trp) [GRCH38: NC_000015.10:g.89325610G>A] variant in POLG gene is interpretated to be a Pathogenic based on ACMG guidelines (PMID: 25741868). This variant meets the following evidence codes reported in the ACMG-guideline. PS1:This variation causes same amino-acid change as an established pathogenic variant. PS4:Prevalence of variant in affecteds statistically increased over controls. PM2:This variant is absent in key population databases. PM3:Detected in trans with a pathogenic variant for Mitochondrial DNA depletion syndrome 4A (Alpers type) which is a recessive disorder. PP1:This variant is co-segregated with Mitochondrial DNA depletion syndrome 4A (Alpers type) in multiple affected family members. PP2:This is a missense variant in POLG with a low rate of benign and high rate of pathogenic missense variations. PP4:Patient's phenotype or family history is highly specific for POLG. Based on the evidence criteria codes applied, the variant is suggested to be Pathogenic. -
This sequence change replaces arginine, which is basic and polar, with tryptophan, which is neutral and slightly polar, at codon 597 of the POLG protein (p.Arg597Trp). This variant is present in population databases (rs139717885, gnomAD 0.009%). This missense change has been observed in individual(s) with clinical features of POLG-related disorders (PMID: 19251978, 20138553, 21880868, 27538604). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 381520). 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 expected to disrupt POLG protein function with a positive predictive value of 95%. For these reasons, this variant has been classified as Pathogenic. -
Inborn genetic diseases Pathogenic:1
The c.1789C>T (p.R597W) alteration is located in exon 10 (coding exon 9) of the POLG gene. This alteration results from a C to T substitution at nucleotide position 1789, causing the arginine (R) at amino acid position 597 to be replaced by a tryptophan (W). for autosomal recessive POLG-related mitochondrial disorders; however, its clinical significance for autosomal dominant POLG-related progressive external ophthalmoplegia is uncertain. Based on data from gnomAD, the T allele has an overall frequency of 0.003% (7/250782) total alleles studied. The highest observed frequency was 0.012% (2/16252) of African alleles. This variant has been identified either homozygous or with a second variant in POLG in multiple individuals with clinical features of POLG-related mitochondrial disorders (Saneto, 2010; Béreau, 2016; Bychkov, 2021; Squires, 2023). Another alteration at the same codon, c.1790G>A (p.R597Q), has been reported (Hou, 2022). This amino acid position is highly conserved in available vertebrate species. This alteration is predicted to be deleterious by in silico analysis. Based on the available evidence, this alteration is classified as pathogenic. -
Sensory ataxic neuropathy, dysarthria, and ophthalmoparesis Pathogenic:1
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Progressive sclerosing poliodystrophy;C1834846:Progressive external ophthalmoplegia with mitochondrial DNA deletions, autosomal dominant 1;C1843851:Sensory ataxic neuropathy, dysarthria, and ophthalmoparesis;C3150914:Mitochondrial DNA depletion syndrome 4b;C4225153:Progressive external ophthalmoplegia with mitochondrial DNA deletions, autosomal recessive 1 Pathogenic:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at