rs200257554

Positions:

chr15-89324156-C-T

Variant summary

Our verdict is Benign. Variant got -9 ACMG points: 0P and 9B. BP4_StrongBP6BS2

The NM_002693.3(POLG):c.2021G>A(p.Gly674Asp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000299 in 1,613,856 control chromosomes in the GnomAD database, including 3 homozygotes. In-silico tool predicts a benign outcome for this variant. 14/21 in silico tools predict a benign outcome for this variant. 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. G674S) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.00017 ( 0 hom., cov: 33)

Exomes 𝑓: 0.00031 ( 3 hom. )

Consequence

POLG
NM_002693.3 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:4B:5

Conservation

PhyloP100: 0.274

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 Benign. Variant got -9 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.008275002).

BP6

Variant 15-89324156-C-T is Benign according to our data. Variant chr15-89324156-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 206462.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=4, Uncertain_significance=4}.

BS2

High Homozygotes in GnomAdExome4 at 3 AD,AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE
POLG	NM_002693.3 linkuse as main transcript	c.2021G>A	p.Gly674Asp	missense_variant	11/23	ENST00000268124.11
POLGARF	NM_001406557.1 linkuse as main transcript	c.*1293G>A		3_prime_UTR_variant	11/23
POLG	NM_001126131.2 linkuse as main transcript	c.2021G>A	p.Gly674Asp	missense_variant	11/23

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
POLG	ENST00000268124.11 linkuse as main transcript	c.2021G>A	p.Gly674Asp	missense_variant	11/23	1	NM_002693.3	P1

Frequencies

GnomAD3 genomes

AF:

0.000171

AC:

AN:

152232

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00490

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.000414

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000882

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.000605

AC:

152

AN:

251084

Hom.:

AF XY:

0.000685

AC XY:

AN XY:

135718

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000868

Gnomad ASJ exome

AF:

0.00735

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00183

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000150

Gnomad OTH exome

AF:

0.000326

GnomAD4 exome

AF:

0.000313

AC:

457

AN:

1461624

Hom.:

Cov.:

AF XY:

0.000396

AC XY:

288

AN XY:

727108

show subpopulations

Gnomad4 AFR exome

AF:

0.000149

Gnomad4 AMR exome

AF:

0.0000671

Gnomad4 ASJ exome

AF:

0.00662

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00195

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000531

Gnomad4 OTH exome

AF:

0.000712

GnomAD4 genome

AF:

0.000171

AC:

AN:

152232

Hom.:

Cov.:

AF XY:

0.000229

AC XY:

AN XY:

74366

show subpopulations

Gnomad4 AFR

AF:

0.0000241

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00490

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.000414

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000882

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.000955

Hom.:

Bravo

AF:

0.000189

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000116

AC:

ExAC

AF:

0.000552

AC:

Asia WGS

AF:

0.000577

AC:

AN:

3478

EpiCase

AF:

0.000218

EpiControl

AF:

0.000178

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:4Benign:5

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:1Benign:1

Likely benign, criteria provided, single submitter	clinical testing	GeneDx	Dec 07, 2020	This variant is associated with the following publications: (PMID: 26557169) -
Uncertain significance, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Mar 01, 2022	- -

Progressive sclerosing poliodystrophy

Benign:2

Likely benign, 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.2021G>A (NP_002684.1:p.Gly674Asp) [GRCH38: NC_000015.10:g.89324156C>T] variant in POLG gene is interpretated to be a Likely Benign based on ACMG guidelines (PMID: 25741868). This variant meets the following evidence codes reported in the ACMG-guideline. BS1:The minor allele frequency of this allele is high for Mitochondrial DNA depletion syndrome 4A (Alpers type). BP4:Computational evidence/predictors indicate no impact on the POLG structure, function, or protein-protein interaction. BP7:The variant is silent with non predicted splice impact. Based on the evidence criteria codes applied, the variant is suggested to be Likely Benign. -
Likely benign, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jan 28, 2024	- -

POLG-Related Spectrum Disorders

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Apr 27, 2017

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases did not allow this variant to be ruled in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance. -

Inborn genetic diseases

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Dec 15, 2017

The p.G674D variant (also known as c.2021G>A), located in coding exon 10 of the POLG gene, results from a G to A substitution at nucleotide position 2021. The glycine at codon 674 is replaced by aspartic acid, an amino acid with similar properties. This alteration was detected in an individual with paroxysmal exertion induced dystonia (PED) and early onset exertion induced dystonia in conjunction with a second POLG alteration of unknown significance (c.3644-27T>G). The p.G674D alteration was also detected in the individual's father. Both the proband and his father also carried the SURF1 c.237G>T alteration which authors considered to be pathogenic; therefore, it is unknown which alteration(s) is causative (Chandra SR et al. J Pediatr Neurosci;10:254-7). This amino acid position is not well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

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

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Center for Genomics, Ann and Robert H. Lurie Children's Hospital of Chicago

Mar 30, 2021

POLG NM_002693 exon 11 p.Gly674Asp (c.2021G>A): This variant has not been reported in the literature but is present in 0.1% (55/30782) of South Asian individuals in the Genome Aggregation Database (http://gnomad.broadinstitute.org/rs200257554). This variant is present in ClinVar (Variation ID:206462). This variant Aspartic Acid (Asp) is present in >5 species (including mammals) and is not well conserved among evolutionarily distant species; this suggests that this variant may not impact the protein. Additional computational prediction tools do not suggest an impact. In summary, data on this variant is insufficient for disease classification. Therefore, the clinical significance of this variant is uncertain. -

not specified

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Eurofins Ntd Llc (ga)

May 07, 2018

- -

POLG-related disorder

Benign:1

Likely benign, no assertion criteria provided

clinical testing

PreventionGenetics, part of Exact Sciences

Apr 26, 2022

This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.061

BayesDel_addAF

Benign

-0.23

BayesDel_noAF

Benign

-0.12

CADD

Benign

7.7

DANN

Benign

0.12

DEOGEN2

Benign

0.18

T;T

Eigen

Benign

-1.0

Eigen_PC

Benign

-0.93

FATHMM_MKL

Benign

0.12

LIST_S2

Benign

0.47

.;T

M_CAP

Uncertain

0.17

MetaRNN

Benign

0.0083

T;T

MetaSVM

Benign

-0.44

MutationAssessor

Benign

0.89

L;L

MutationTaster

Benign

1.0

N;N

PrimateAI

Benign

0.25

PROVEAN

Benign

1.2

N;N

REVEL

Uncertain

0.38

Sift

Benign

0.98

T;T

Sift4G

Benign

0.89

T;T

Polyphen

0.0

B;B

Vest4

0.19

MVP

0.71

MPC

0.20

ClinPred

0.0023

GERP RS

2.3

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.1

Varity_R

0.019

gMVP

0.46

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.020

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