15-89329055-A-C
Variant summary
Our verdict is Pathogenic. The variant received 14 ACMG points: 14P and 0B. PM1PP3_StrongPP5_Very_Strong
The NM_002693.3(POLG):c.911T>G(p.Leu304Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000236 in 1,613,046 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
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 14 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000328 AC: 5AN: 152216Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.0000566 AC: 14AN: 247470 AF XY: 0.0000822 show subpopulations
GnomAD4 exome AF: 0.0000226 AC: 33AN: 1460830Hom.: 0 Cov.: 33 AF XY: 0.0000289 AC XY: 21AN XY: 726682 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.0000328 AC: 5AN: 152216Hom.: 0 Cov.: 32 AF XY: 0.0000134 AC XY: 1AN XY: 74368 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
Progressive external ophthalmoplegia with mitochondrial DNA deletions, autosomal recessive 1 Pathogenic:5
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A Hetrozygous variation in exon 4 of the POLG gene that results in the aminoacid substitution of Arginine for Leucine at codon 304 was detected.The observed variant c.911T>G (p.Leu304Arg) has not been reported in the 1000 genomes and ExAC databases. The in silico prediction of the variant are possibly damaging by PolyPhen-2 (HumDiv) and damaging by LRT and MutationTaster2. The reference codon is conserved across species.In summary, the variant meets our criteria to be classified as pathogenic. -
PM3, PP5, PM2, PP3, PS3_Supporting, PM1, PP1, PP2 -
Progressive sclerosing poliodystrophy Pathogenic:5
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The variant c.911 T>G (p.Leu304Arg) is present in compound heterozygous state with c.368 T>G (p.Val123Gly) in POLG gene. The four month old patient had two episodes of pneumonia and Acute Respiratory Distress Syndrome. Other clinical features observed were severe sepsis, shock, reduced IgG and increased levels of CK, Ferritin, SGOT and FGF-21. This variant has been present in 0.036% in gnomAD and 0.0074% in ExAc. The c.911 variant was observed 'in trans' with c.368 variant as both segregated separately in mother and father of the proband. This variant has been reported previously PMID: 32567010. Based on segregation studies and the clinical features, this variant is classified as Pathogenic. -
This sequence change replaces leucine, which is neutral and non-polar, with arginine, which is basic and polar, at codon 304 of the POLG protein (p.Leu304Arg). This variant is present in population databases (rs121918044, gnomAD 0.04%). This missense change has been observed in individual(s) with autosomal recessive POLG-related disorders (PMID: 11431686, 16639411, 21880868, 22006280, 24288107). 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: 13497). 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%. Experimental studies have shown that this missense change affects POLG function (PMID: 20601675, 26095671). For these reasons, this variant has been classified as Pathogenic. -
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The NM_002693.2:c.911T>G (NP_002684.1:p.Leu304Arg) [GRCH38: NC_000015.10:g.89329055A>C] variant in POLG gene is interpretated to be a Likely Pathogenic based on ACMG guidelines (PMID: 25741868). This variant has been reported in PMID:11431686 . This variant meets the following evidence codes reported in the ACMG-guideline. 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 Likely Pathogenic. -
not provided Pathogenic:4
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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: 24288107, 20601675, 16639411, 21880868, 16368709, 22006280, 11431686, 30634555, 31521625, 32161153, 31589614, 33469851) -
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POLG-related disorder Pathogenic:2
The POLG c.911T>G variant is predicted to result in the amino acid substitution p.Leu304Arg. This variant has been reported in the compound heterozygous or homozygous states in patients with a POLG-related disorder, such as Alpers-Huttenlocher syndrome, autosomal recessive progressive external ophthalmoplegia, or sensory ataxic neuropathy, dysarthria, and ophthalmoparesis (SANDO) (Spiegler et al. 2011. PubMed ID: 22006280; Szczepanowska et al. 2010. PubMed ID: 20601675). This variant is reported in 0.036% of alleles in individuals of South Asian descent in gnomAD. This variant is interpreted as pathogenic. -
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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;C4551995:Mitochondrial DNA depletion syndrome 1 Pathogenic:1
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Inborn genetic diseases 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