chr15-89321996-G-C
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Variant summary
Our verdict is Uncertain significance. Variant got 1 ACMG points: 1P and 0B. PP3
The NM_002693.3(POLG):āc.2446C>Gā(p.Leu816Val) variant causes a missense change. The variant allele was found at a frequency of 0.000026 in 1,461,870 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 Uncertain significance (ā ā ).
Frequency
Genomes: not found (cov: 33)
Exomes š: 0.000026 ( 0 hom. )
Consequence
POLG
NM_002693.3 missense
NM_002693.3 missense
Scores
6
9
3
Clinical Significance
Conservation
PhyloP100: 4.96
Genes affected
POLG (HGNC:9179): (DNA polymerase gamma, catalytic subunit) Mitochondrial DNA polymerase is heterotrimeric, consisting of a homodimer of accessory subunits plus a catalytic subunit. The protein encoded by this gene is the catalytic subunit of mitochondrial DNA polymerase. The encoded protein contains a polyglutamine tract near its N-terminus that may be polymorphic. Defects in this gene are a cause of progressive external ophthalmoplegia with mitochondrial DNA deletions 1 (PEOA1), sensory ataxic neuropathy dysarthria and ophthalmoparesis (SANDO), Alpers-Huttenlocher syndrome (AHS), and mitochondrial neurogastrointestinal encephalopathy syndrome (MNGIE). Two transcript variants encoding the same protein have been found for this gene. [provided by RefSeq, Jul 2008]
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ACMG classification
Classification made for transcript
Verdict is Uncertain_significance. Variant got 1 ACMG points.
PP3
MetaRNN computational evidence supports a deleterious effect, 0.807
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | MANE | UniProt |
---|---|---|---|---|---|---|---|
POLG | NM_002693.3 | c.2446C>G | p.Leu816Val | missense_variant | 15/23 | ENST00000268124.11 | |
POLGARF | NM_001406557.1 | c.*1718C>G | 3_prime_UTR_variant | 15/23 | |||
POLG | NM_001126131.2 | c.2446C>G | p.Leu816Val | missense_variant | 15/23 |
Ensembl
Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | TSL | MANE | Appris | UniProt |
---|---|---|---|---|---|---|---|---|---|
POLG | ENST00000268124.11 | c.2446C>G | p.Leu816Val | missense_variant | 15/23 | 1 | NM_002693.3 | P1 |
Frequencies
GnomAD3 genomes Cov.: 33
GnomAD3 genomes
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33
GnomAD3 exomes AF: 0.0000159 AC: 4AN: 251458Hom.: 0 AF XY: 0.0000221 AC XY: 3AN XY: 135920
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GnomAD4 exome AF: 0.0000260 AC: 38AN: 1461870Hom.: 0 Cov.: 32 AF XY: 0.0000220 AC XY: 16AN XY: 727244
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GnomAD4 genome Cov.: 33
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ClinVar
Significance: Uncertain significance
Submissions summary: Uncertain:4
Revision: criteria provided, multiple submitters, no conflicts
LINK: link
Submissions by phenotype
Progressive sclerosing poliodystrophy Uncertain:2
Uncertain significance, criteria provided, single submitter | clinical testing | Invitae | Jan 27, 2024 | This sequence change replaces leucine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 816 of the POLG protein (p.Leu816Val). This variant is present in population databases (rs748262645, gnomAD 0.004%). This variant has not been reported in the literature in individuals affected with POLG-related conditions. ClinVar contains an entry for this variant (Variation ID: 379675). 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) has been performed at Invitae 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. 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. - |
Uncertain significance, criteria provided, single submitter | clinical testing | Wong Mito Lab, Molecular and Human Genetics, Baylor College of Medicine | Oct 01, 2018 | The NM_002693.2:c.2446C>G (NP_002684.1:p.Leu816Val) [GRCH38: NC_000015.10:g.89321996G>C] variant in POLG gene is interpretated to be a Uncertain Significance based on ACMG guidelines (PMID: 25741868). This variant meets the following evidence codes reported in the ACMG-guideline. BP4:Computational evidence/predictors indicate no impact on the POLG structure, function, or protein-protein interaction. Based on the evidence criteria codes applied, the variant is suggested to be Uncertain Significance. - |
POLG-related disorder Uncertain:1
Uncertain significance, criteria provided, single submitter | clinical testing | PreventionGenetics, part of Exact Sciences | Nov 21, 2022 | The POLG c.2446C>G variant is predicted to result in the amino acid substitution p.Leu816Val. To our knowledge, this variant has not been reported in the literature. This variant is reported in 0.0035% of alleles in individuals of European (Non-Finnish) descent in gnomAD (http://gnomad.broadinstitute.org/variant/15-89865227-G-C). At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. - |
not provided Uncertain:1
Uncertain significance, criteria provided, single submitter | clinical testing | GeneDx | Sep 23, 2016 | The L816V variant in the POLG gene has not been reported previously as a pathogenic variant, nor as a benign variant, to our knowledge. The L816V 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 L816V variant is a conservative amino acid substitution, which is not likely to impact secondary protein structure as these residues share similar properties. This substitution occurs at a position that is conserved across species. In silico analysis is inconsistent in its predictions as to whether or not the variant is damaging to the protein structure/function. We interpret L816V as a variant of uncertain significance. - |
Computational scores
Source:
Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
BayesDel_addAF
Pathogenic
D
BayesDel_noAF
Pathogenic
CADD
Pathogenic
DANN
Uncertain
DEOGEN2
Uncertain
D;D
Eigen
Uncertain
Eigen_PC
Uncertain
FATHMM_MKL
Pathogenic
D
M_CAP
Uncertain
D
MetaRNN
Pathogenic
D;D
MetaSVM
Pathogenic
D
MutationAssessor
Uncertain
M;M
MutationTaster
Benign
D;D
PrimateAI
Uncertain
T
PROVEAN
Benign
N;N
REVEL
Pathogenic
Sift
Uncertain
D;D
Sift4G
Uncertain
D;D
Polyphen
D;D
Vest4
MutPred
Loss of sheet (P = 0.0817);Loss of sheet (P = 0.0817);
MVP
MPC
ClinPred
D
GERP RS
Varity_R
gMVP
Splicing
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SpliceAI score (max)
Details are displayed if max score is > 0.2
Find out detailed SpliceAI scores and Pangolin per-transcript scores at