rs1001570418
Variant summary
Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM1PM5
The NM_002693.3(POLG):c.1790G>A(p.Arg597Gln) variant causes a missense change. The variant allele was found at a frequency of 0.00000496 in 1,613,604 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R597G) 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: Uncertain_significance. The variant received 4 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.00000657 AC: 1AN: 152190Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.00000399 AC: 1AN: 250900 AF XY: 0.00000737 show subpopulations
GnomAD4 exome AF: 0.00000479 AC: 7AN: 1461414Hom.: 0 Cov.: 33 AF XY: 0.00000413 AC XY: 3AN XY: 727052 show subpopulations
GnomAD4 genome AF: 0.00000657 AC: 1AN: 152190Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1AN XY: 74334 show subpopulations
ClinVar
Submissions by phenotype
not provided Uncertain:3
POLG: PM2, PM3:Supporting, PM5:Supporting, PP3 -
PM2, PM3_supporting, PM5 -
Not observed at a significant frequency in large population cohorts (Lek et al., 2016); In silico analysis supports that this missense variant does not alter protein structure/function -
Progressive sclerosing poliodystrophy Pathogenic:1Uncertain:1
The NM_002693.2:c.1790G>A (NP_002684.1:p.Arg597Gln) [GRCH38: NC_000015.10:g.89325609C>T] 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. 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. PP3:Computational evidence/predictors indicate the variant has deleterious effect on POLG structure, function, or protein-protein interaction. 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 glutamine, which is neutral and polar, at codon 597 of the POLG protein (p.Arg597Gln). This variant is present in population databases (no rsID available, gnomAD 0.0009%). This missense change has been observed in individual(s) with progressive external ophthalmoplegia (PMID: 35289132). ClinVar contains an entry for this variant (Variation ID: 576551). Invitae Evidence 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 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 POLG protein function. This variant disrupts the p.Arg597 amino acid residue in POLG. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 19251978, 20138553, 21880868, 27538604). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. 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. -
not specified Uncertain:1
Variant summary: POLG c.1790G>A (p.Arg597Gln) results in a conservative amino acid change to a highly conserved residue (HGMD) in the encoded protein sequence. Another missense variant altering this residue (p.Arg597Trp) is classified as pathogenic/likely pathgenic in ClinVar. Three of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 4e-06 in 250900 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.1790G>A has been reported in the literature in an individual affected with progressive external ophthalmoplegia who was reported as compound heterozygous with a likely pathogenic variant (Hou_2022). These data suggest the variant may be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Three submitters have provided clinical-significance assessments for this variant to ClinVar after 2014, and classified it as pathogenic (n=1) or uncertain significance (n=2). Based on the evidence outlined above, the variant was classified as VUS-possibly pathogenic. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at