15-89321007-T-G

Variant names:

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PP3_ModeratePP5_Very_Strong

The NM_002693.3(POLG):c.2740A>C(p.Thr914Pro) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000187 in 1,614,050 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 Pathogenic (★★).

Frequency

Genomes: 𝑓 0.000072 ( 0 hom., cov: 33)

Exomes 𝑓: 0.00020 ( 0 hom. )

Consequence

POLG
NM_002693.3 missense

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:16

Conservation

PhyloP100: 7.67

Variant links:

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]

POLG links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 10 ACMG points.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.924

PP5

Variant 15-89321007-T-G is Pathogenic according to our data. Variant chr15-89321007-T-G is described in ClinVar as [Pathogenic]. Clinvar id is 279961.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr15-89321007-T-G is described in Lovd as [Pathogenic]. Variant chr15-89321007-T-G is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
POLG	NM_002693.3 link	c.2740A>C	p.Thr914Pro	missense_variant	Exon 18 of 23	ENST00000268124.11	NP_002684.1	P54098E5KNU5
POLG	NM_001126131.2 link	c.2740A>C	p.Thr914Pro	missense_variant	Exon 18 of 23		NP_001119603.1	P54098E5KNU5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
POLG	ENST00000268124.11 link	c.2740A>C	p.Thr914Pro	missense_variant	Exon 18 of 23	1	NM_002693.3	ENSP00000268124.5		P54098

Frequencies

GnomAD3 genomes

AF:

0.0000723

AC:

AN:

152236

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.000147

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.000112

AC:

AN:

250820

Hom.:

AF XY:

0.000103

AC XY:

AN XY:

135632

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000247

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.000199

AC:

291

AN:

1461814

Hom.:

Cov.:

AF XY:

0.000190

AC XY:

138

AN XY:

727208

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.000256

Gnomad4 OTH exome

AF:

0.0000993

GnomAD4 genome

AF:

0.0000723

AC:

AN:

152236

Hom.:

Cov.:

AF XY:

0.0000807

AC XY:

AN XY:

74370

show subpopulations

Gnomad4 AFR

AF:

0.0000241

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.000147

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.000133

Hom.:

Bravo

AF:

0.000110

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000349

AC:

ExAC

AF:

0.000123

AC:

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:16

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Pathogenic:7

Mar 07, 2016

Mayo Clinic Laboratories, Mayo Clinic

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Diagnostic Laboratory, Department of Genetics, University Medical Center Groningen

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Oct 26, 2022

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Accounts for approximately 3% of disease-causing alleles and has been identified in patients with autosomal recessive POLG-related disorders, including Alpers syndrome and mitochondrial spinocerebellar ataxia and epilepsy (MSCAE) (Wong et al. 2008; Horvath et al. 2006; Taanman et al. 2009; Hinnell et al. 2012); Published functional studies demonstrate a damaging effect (Roos et al., 2013); 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: 16545482, 24642831, 20138553, 18487244, 30021052, 32042919, 23446635, 18828154, 16621917, 21357833, 18546365, 21956653, 16639411, 19578034, 23084792, 23446645, 21282586, 20843780, 27450679, 28471437, 30167885, 31425757, 25160553, 23921535, 21880868, 31980526) -

Feb 09, 2023

Athena Diagnostics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The frequency of this variant in the general population is consistent with pathogenicity (http://gnomad.broadinstitute.org). This variant has been identified in individuals with autosomal recessive POLG-related disorders and appears to segregate with disease in at least one family. Assessment of experimental evidence suggests this variant results in abnormal protein function. A study shows this variant impairs DNA binding affinity and DNA polymerase activity compared to wild-type (PMID: 23446635). In multiple individuals, this variant has been seen with a single recessive pathogenic variant in the same gene, suggesting this variant may also be pathogenic. -

Sep 05, 2017

Eurofins Ntd Llc (ga)

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Laboratory of Diagnostic Genome Analysis, Leiden University Medical Center (LUMC)

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Progressive sclerosing poliodystrophy

Pathogenic:3

Sep 29, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces threonine, which is neutral and polar, with proline, which is neutral and non-polar, at codon 914 of the POLG protein (p.Thr914Pro). This variant is present in population databases (rs139590686, gnomAD 0.02%). This missense change has been observed in individual(s) with autosomal recessive adult onset progressive external ophthalmoplegia in a single family (PMID: 23446645). This variant has also been reported, along with a second, rare POLG variant in several individuals affected with a POLG-related disorder (PMID: 16621917, 21956653, 18487244, 21880868, 23921535, 20843780, 21357833, 21282586) including several individuals affected with Alpers syndrome (PMID: 16545482, 16639411, 18546365, 18828154, 23446635, 24642831, 27450679). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 279961). 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) 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: 18828154, 23446635). For these reasons, this variant has been classified as Pathogenic. -

Mar 20, 2024

Baylor Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Oct 01, 2018

Wong Mito Lab, Molecular and Human Genetics, Baylor College of Medicine

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The NM_002693.2:c.2740A>C (NP_002684.1:p.Thr914Pro) [GRCH38: NC_000015.10:g.89321007T>G] variant in POLG gene is interpretated to be a Pathogenic based on ACMG guidelines (PMID: 25741868). This variant has been reported in PMID:16621917 . 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. PS3:Well established functional studies show a deleterious effect on POLG. 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. 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. -

POLG-Related Spectrum Disorders

Pathogenic:1

Apr 27, 2017

Illumina Laboratory Services, Illumina

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

POLG-related disorder

Pathogenic:1

Mar 20, 2024

PreventionGenetics, part of Exact Sciences

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

The POLG c.2740A>C variant is predicted to result in the amino acid substitution p.Thr914Pro. This variant has been reported in the heterozygous and compound heterozygous states in multiple individuals with POLG-related disorders (see for example, Table 1, Horvath et al. 2006. PubMed ID: 16621917; Table 3, Wong et al. 2008. PubMed ID: 18546365; Table 1, Papandreou et al. 2018. PubMed ID: 30167885). This variant is reported in 0.024% of alleles in individuals of European (non-Finnish) descent in gnomAD. An in vitro experimental study suggests this variant affects polymerase gamma mtDNA binding and synthesis (Figure 2, Roos et al. 2013. PubMed ID: 23446635). This variant is interpreted as pathogenic. -

Tip-toe gait

Pathogenic:1

Oct 01, 2021

Practice for Gait Abnormalities, David Pomarino, Competency Network Toe Walking c/o Practice Pomarino

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Hereditary motor sensory neuropathy (HMSN), also known as Charcot-Marie-Tooth Disease (CMT), is the most commonly inherited peripheral polyneuropathy. It constitutes a group of inherited, progressive, motor and sensory peripheral nerve disorders with properties of demyelination, axonal degeneration, or both. It is classified by clinical characteristics, modes of inheritance, electrophysiologic features, metabolic defects, and specific gene markers. Our patients all walk on tiptoe, so they show similar symptoms. When we genetically test them with our toe walking panel, we find that around 90 per cent of them have a genetic variant that explains their toe walking. These can be assigned, for example, to the area of myopathies (such as variants of the COL6A3 gene), the area of hereditary neuropathies (such as variants of the KMT2C gene) or the area of metabolic diseases (such as variants of the PYGM gene). In a smaller group of patients with almost identical symptoms, no abnormality is found in the genes of our panel, but spastic paraplegia can be detected. In another small group of our toe walkers, no abnormalities can be detected in the genes analysed in our toe walking panel, nor do they suffer from spastic paraplegia, as is also the case with healthy children. In contrast to these, however, they show a tiptoe gait. These patients suffer from infantile cerebral palsy, in which toe walking can also be observed. -

Mitochondrial DNA depletion syndrome 4b

Pathogenic:1

Sep 02, 2022

Victorian Clinical Genetics Services, Murdoch Childrens Research Institute

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as Pathogenic. Following criteria are met: 0102 - Loss of function is a known mechanism of disease in this gene and is associated with POLG-related disorders. (I) 0108 - This gene is associated with both recessive and dominant disease. Variants are usually inherited in a recessive manner, however progressive external ophthalmoplegia can also be dominant when heterozygous variants are located in the highly conserved active site of motif B of the polymerase domain (PMID: 30451971). (I) 0200 - Variant is predicted to result in a missense amino acid change from threonine to proline. (I) 0251 - This variant is heterozygous. (I) 0304 - Variant is present in gnomAD (v2) <0.01 (31 heterozygotes, 0 homozygotes). (SP) 0501 - Missense variant consistently predicted to be damaging by multiple in silico tools or highly conserved with a major amino acid change. (SP) 0600 - Variant is located in the annotated DNA polymerase family A domain (DECIPHER). (I) 0801 - This variant has strong previous evidence of pathogenicity in unrelated individuals. This variant has been classified as pathogenic or likely pathogenic by multiple clinical laboratories in ClinVar and has been observed as compound heterozygous in individuals with POLG-related conditions (PMIDs: 30167885, 18546365). (SP) 1205 - This variant has been shown to be maternally inherited (by trio analysis). (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -

Progressive sclerosing poliodystrophy;C3150914:Mitochondrial DNA depletion syndrome 4b

Pathogenic:1

Baylor Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

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

May 18, 2024

Fulgent Genetics, Fulgent Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.86

BayesDel_addAF

Pathogenic

0.37

BayesDel_noAF

Pathogenic

0.58

CADD

Uncertain

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.97

D;D

Eigen

Pathogenic

0.80

Eigen_PC

Pathogenic

0.71

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Uncertain

0.86

.;D

M_CAP

Pathogenic

0.52

MetaRNN

Pathogenic

0.92

D;D

MetaSVM

Pathogenic

1.1

MutationAssessor

Pathogenic

3.5

M;M

PrimateAI

Uncertain

0.71

PROVEAN

Pathogenic

-5.8

D;D

REVEL

Pathogenic

0.98

Sift

Pathogenic

0.0

D;D

Sift4G

Uncertain

0.0030

D;D

Polyphen

1.0

D;D

Vest4

0.72

MVP

0.99

MPC

0.75

ClinPred

0.78

GERP RS

5.2

Varity_R

0.96

gMVP

0.91

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.0

Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

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