15-89325505-C-T

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM1BP4_Strong

The NM_002693.3(POLG):c.1894G>A(p.Ala632Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000373 in 1,610,406 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 17/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. A632A) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000034 ( 0 hom. )

Consequence

POLG
NM_002693.3 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:3

Conservation

PhyloP100: -0.0370

Publications

0 publications found

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 Gene-Disease associations (from GenCC):

progressive external ophthalmoplegia with mitochondrial DNA deletions, autosomal dominant 1
Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae), Ambry Genetics
mitochondrial DNA depletion syndrome 4a
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Ambry Genetics, Laboratory for Molecular Medicine, Labcorp Genetics (formerly Invitae), Orphanet, G2P
sensory ataxic neuropathy, dysarthria, and ophthalmoparesis
Inheritance: AR Classification: DEFINITIVE, SUPPORTIVE Submitted by: Ambry Genetics, Orphanet, G2P
autosomal dominant progressive external ophthalmoplegia
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
autosomal recessive progressive external ophthalmoplegia
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
mitochondrial neurogastrointestinal encephalomyopathy
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
recessive mitochondrial ataxia syndrome
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
spinocerebellar ataxia with epilepsy
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
Leigh syndrome
Inheritance: AR Classification: LIMITED Submitted by: ClinGen

POLG links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -2 ACMG points.

PM1

In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 17 uncertain in NM_002693.3

BP4

Computational evidence support a benign effect (MetaRNN=0.05485785).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
POLG	NM_002693.3 link	c.1894G>A	p.Ala632Thr	missense_variant	Exon 10 of 23	ENST00000268124.11	NP_002684.1
POLG	NM_001126131.2 link	c.1894G>A	p.Ala632Thr	missense_variant	Exon 10 of 23		NP_001119603.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
POLG	ENST00000268124.11 link	c.1894G>A	p.Ala632Thr	missense_variant	Exon 10 of 23	1	NM_002693.3	ENSP00000268124.5

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152148

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

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

GnomAD2 exomes

AF:

0.00

AC:

AN:

248202

AF XY:

0.00

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 FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000343

AC:

AN:

1458258

Hom.:

Cov.:

AF XY:

0.00000276

AC XY:

AN XY:

725602

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33478

American (AMR)

AF:

0.00

AC:

AN:

44720

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39698

South Asian (SAS)

AF:

0.00

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

49848

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00000450

AC:

AN:

1111976

Other (OTH)

AF:

0.00

AC:

AN:

60376

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152148

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74308

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41432

American (AMR)

AF:

0.00

AC:

AN:

15282

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5184

South Asian (SAS)

AF:

0.00

AC:

AN:

4826

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10612

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68026

Other (OTH)

AF:

0.00

AC:

AN:

2086

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.575

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Progressive sclerosing poliodystrophy

Uncertain:2

Oct 02, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces alanine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 632 of the POLG protein (p.Ala632Thr). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with POLG-related conditions. ClinVar contains an entry for this variant (Variation ID: 597713). 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 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.

Oct 01, 2018

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

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The NM_002693.2:c.1894G>A (NP_002684.1:p.Ala632Thr) [GRCH38: NC_000015.10:g.89325505C>T] variant in POLG gene is interpretated to be a Uncertain Significance 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. Based on the evidence criteria codes applied, the variant is suggested to be Uncertain Significance.

not provided

Uncertain:1

Jul 03, 2018

Eurofins Ntd Llc (ga)

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.070

BayesDel_addAF

Benign

0.0011

BayesDel_noAF

Benign

-0.24

CADD

Benign

(source)

DANN

Benign

0.67

DEOGEN2

Benign

0.20

T;T

Eigen

Benign

-0.96

Eigen_PC

Benign

-0.84

LIST_S2

Benign

0.0

.;T

M_CAP

Benign

0.060

MetaRNN

Benign

0.055

T;T

MetaSVM

Uncertain

-0.24

MutationAssessor

Benign

0.55

N;N

PhyloP100

-0.037

PrimateAI

Benign

0.29

PROVEAN

Benign

0.28

N;N

Sift

Benign

0.61

T;T

Sift4G

Benign

0.61

T;T

Vest4

0.11

ClinPred

0.023

GERP RS

2.2

Varity_R

0.064

gMVP

0.37

Mutation Taster

=97/3

polymorphism

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.040

Details are displayed if max score is > 0.2

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over