chr15-89324150-G-A

Position:

chr15-89324150-G-A

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 0P and 2B. BP4_Moderate

The NM_002693.3(POLG):c.2027C>T(p.Ala676Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000651 in 1,613,768 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. A676A) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000069 ( 0 hom. )

Consequence

POLG
NM_002693.3 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:6B:1

Conservation

PhyloP100: 2.34

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 Likely_benign. Variant got -2 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.11224708).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
POLG	NM_002693.3 linkuse as main transcript	c.2027C>T	p.Ala676Val	missense_variant	11/23	ENST00000268124.11	NP_002684.1	P54098E5KNU5
POLG	NM_001126131.2 linkuse as main transcript	c.2027C>T	p.Ala676Val	missense_variant	11/23		NP_001119603.1	P54098E5KNU5
POLGARF	NM_001406557.1 linkuse as main transcript	c.*1299C>T		3_prime_UTR_variant	11/23

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
POLG	ENST00000268124.11 linkuse as main transcript	c.2027C>T	p.Ala676Val	missense_variant	11/23	1	NM_002693.3	ENSP00000268124.5		P54098

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

152184

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000724

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:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000876

AC:

AN:

251098

Hom.:

AF XY:

0.0000810

AC XY:

AN XY:

135722

show subpopulations

Gnomad AFR exome

AF:

0.0000615

Gnomad AMR exome

AF:

0.000463

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.0000466

Gnomad NFE exome

AF:

0.0000264

Gnomad OTH exome

AF:

0.000163

GnomAD4 exome

AF:

0.0000691

AC:

101

AN:

1461584

Hom.:

Cov.:

AF XY:

0.0000674

AC XY:

AN XY:

727098

show subpopulations

Gnomad4 AFR exome

AF:

0.0000597

Gnomad4 AMR exome

AF:

0.000425

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000252

Gnomad4 SAS exome

AF:

0.0000116

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000665

Gnomad4 OTH exome

AF:

0.0000662

GnomAD4 genome

AF:

0.0000263

AC:

AN:

152184

Hom.:

Cov.:

AF XY:

0.0000404

AC XY:

AN XY:

74338

show subpopulations

Gnomad4 AFR

AF:

0.0000724

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:

0.0000147

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000422

Hom.:

Bravo

AF:

0.0000529

TwinsUK

AF:

0.000270

AC:

ALSPAC

AF:

0.00

AC:

ESP6500AA

AF:

0.000227

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.000115

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:6Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:3

Uncertain significance, criteria provided, single submitter	clinical testing	Athena Diagnostics	May 02, 2023	Available data are insufficient to determine the clinical significance of the variant at this time. The frequency of this variant in the general population is uninformative in assessment of its pathogenicity (http://gnomad.broadinstitute.org). Computational tools predict that this variant is not damaging. -
Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Jul 22, 2024	Observed in heterozygous state in two individuals with features suggestive POLG deficiency (PMID: 21880868); In silico analysis indicates that this missense variant does not alter protein structure/function; This variant is associated with the following publications: (PMID: Betler2024[Review], 21880868) -
Uncertain significance, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	May 30, 2018	- -

Progressive sclerosing poliodystrophy

Uncertain:1Benign:1

Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jan 24, 2024	This sequence change replaces alanine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 676 of the POLG protein (p.Ala676Val). This variant is present in population databases (rs376306906, gnomAD 0.05%). This missense change has been observed in individual(s) with develomental delay, hypotonia, encephalopathy, ataxia, seizure, myoclonus, pyramidal signs, intractable seizure, spasticity (PMID: 21880868). ClinVar contains an entry for this variant (Variation ID: 451086). 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 not expected to disrupt POLG protein function with a negative predictive value of 95%. 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. -
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.2027C>T (NP_002684.1:p.Ala676Val) [GRCH38: NC_000015.10:g.89324150G>A] 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. 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. -

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

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Oct 31, 2018

- -

Inborn genetic diseases

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jun 07, 2017

The p.A676V variant (also known as c.2027C>T), located in coding exon 10 of the POLG gene, results from a C to T substitution at nucleotide position 2027. The alanine at codon 676 is replaced by valine, an amino acid with similar properties. 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. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.084

BayesDel_addAF

Benign

-0.15

BayesDel_noAF

Benign

-0.11

CADD

Benign

DANN

Uncertain

0.99

DEOGEN2

Benign

0.38

T;T

Eigen

Benign

-0.33

Eigen_PC

Benign

-0.29

FATHMM_MKL

Benign

0.24

LIST_S2

Benign

0.67

.;T

M_CAP

Pathogenic

0.29

MetaRNN

Benign

0.11

T;T

MetaSVM

Uncertain

-0.11

MutationAssessor

Uncertain

2.3

M;M

PrimateAI

Benign

0.29

PROVEAN

Benign

-0.80

N;N

REVEL

Benign

0.28

Sift

Benign

0.31

T;T

Sift4G

Benign

0.28

T;T

Polyphen

0.76

P;P

Vest4

0.11

MVP

0.91

MPC

0.15

ClinPred

0.042

GERP RS

4.2

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.1

Varity_R

0.034

gMVP

0.47

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