15-89321007-T-G

Position:

chr15-89321007-T-G

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PM1PM5PP3_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 Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. T914A) has been classified as Likely 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:15

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:

POLGARF (HGNC:):

POLGARF links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 14 ACMG points.

PM1

In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 8 uncertain in NM_002693.3

PM5

Other missense variant is known to change same aminoacid residue: Variant chr15-89321007-T-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 2736250.Status of the report is criteria_provided_single_submitter, 1 stars.

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 [Likely_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/exons	MANE
POLG	NM_002693.3 linkuse as main transcript	c.2740A>C	p.Thr914Pro	missense_variant	18/23	ENST00000268124.11
POLGARF	NM_001406557.1 linkuse as main transcript	c.*2012A>C		3_prime_UTR_variant	18/23
POLG	NM_001126131.2 linkuse as main transcript	c.2740A>C	p.Thr914Pro	missense_variant	18/23

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
POLG	ENST00000268124.11 linkuse as main transcript	c.2740A>C	p.Thr914Pro	missense_variant	18/23	1	NM_002693.3	P1

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:15

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Pathogenic:7

Pathogenic, no assertion criteria provided	clinical testing	Diagnostic Laboratory, Department of Genetics, University Medical Center Groningen	-	- -
Likely pathogenic, no assertion criteria provided	clinical testing	Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Oct 26, 2022	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) -
Pathogenic, criteria provided, single submitter	clinical testing	Athena Diagnostics	Feb 09, 2023	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. -
Pathogenic, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Sep 05, 2017	- -
Pathogenic, no assertion criteria provided	clinical testing	Mayo Clinic Laboratories, Mayo Clinic	Mar 07, 2016	- -
Pathogenic, no assertion criteria provided	clinical testing	Laboratory of Diagnostic Genome Analysis, Leiden University Medical Center (LUMC)	-	- -

Progressive sclerosing poliodystrophy

Pathogenic:3

Pathogenic, 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.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. -
Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Mar 20, 2024	- -
Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Jan 29, 2024	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). 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: 18828154, 23446635). For these reasons, this variant has been classified as Pathogenic. -

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

Pathogenic, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Nov 18, 2021

- -

POLG-Related Spectrum Disorders

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Apr 27, 2017

- -

POLG-related disorder

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

PreventionGenetics, part of Exact Sciences

Nov 27, 2023

The POLG c.2740A>C variant is predicted to result in the amino acid substitution p.Thr914Pro. This variant has been reported to be pathogenic for POLG-related disorders (Horvath et al. 2006. PubMed ID: 16621917; Wong et al. 2008. PubMed ID: 18546365; Tang et al. 2011. PubMed ID: 21880868; Hedberg-Oldfors et al. 2020. PubMed ID: 32042919). The majority of affected patients who carry this variant harbor a second pathogenic variant on the opposite allele (in trans), resulting in autosomal recessive disease. At least one patient, who presented with progressive external ophthalmoplegia (PEO), carried this variant in the heterozygous state alone (Wong et al. 2008. PubMed ID: 18546365). This variant is reported in 0.024% of alleles in individuals of European (Non-Finnish) descent in gnomAD (http://gnomad.broadinstitute.org/variant/15-89864238-T-G). This variant is interpreted as pathogenic. -

Tip-toe gait

Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

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

Oct 01, 2021

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. -

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

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Baylor Genetics

- -

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

MutationTaster

Benign

1.0

D;D

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

Other links and lift over