15-89325610-G-A
Variant summary
Our verdict is Pathogenic. The variant received 16 ACMG points: 16P and 0B. PM1PM5PP3_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 (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R597Q) has been classified as Likely pathogenic.
Frequency
Consequence
NM_002693.3 missense
Scores
Clinical Significance
Conservation
Publications
- progressive external ophthalmoplegia with mitochondrial DNA deletions, autosomal dominant 1Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae), Ambry Genetics
- mitochondrial DNA depletion syndrome 4aInheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Ambry Genetics, Laboratory for Molecular Medicine, Labcorp Genetics (formerly Invitae), Orphanet, G2P
- sensory ataxic neuropathy, dysarthria, and ophthalmoparesisInheritance: AR Classification: DEFINITIVE, SUPPORTIVE Submitted by: Ambry Genetics, Orphanet, G2P
- autosomal dominant progressive external ophthalmoplegiaInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- autosomal recessive progressive external ophthalmoplegiaInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
- mitochondrial neurogastrointestinal encephalomyopathyInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
- recessive mitochondrial ataxia syndromeInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
- spinocerebellar ataxia with epilepsyInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
- Leigh syndromeInheritance: AR Classification: LIMITED Submitted by: ClinGen
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ACMG classification
Our verdict: Pathogenic. The variant received 16 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000131 AC: 2AN: 152186Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.0000279 AC: 7AN: 250782 AF XY: 0.0000221 show subpopulations
GnomAD4 exome AF: 0.0000144 AC: 21AN: 1461222Hom.: 0 Cov.: 33 AF XY: 0.0000165 AC XY: 12AN XY: 726968 show subpopulations
GnomAD4 genome AF: 0.0000131 AC: 2AN: 152304Hom.: 0 Cov.: 32 AF XY: 0.0000269 AC XY: 2AN XY: 74466 show subpopulations
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
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. -
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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