15-89322776-T-G

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 4P and 1B. PM1PM2BP4

The NM_002693.3(POLG):c.2392A>C(p.Ile798Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000131 in 152,126 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. I798V) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 33)

Consequence

POLG
NM_002693.3 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:2

Conservation

PhyloP100: 3.21

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: Uncertain_significance. The variant received 3 ACMG points.

PM1

In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 14 uncertain in NM_002693.3

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.3715885).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
POLG	NM_002693.3 link	c.2392A>C	p.Ile798Leu	missense_variant	Exon 14 of 23	ENST00000268124.11	NP_002684.1
POLG	NM_001126131.2 link	c.2392A>C	p.Ile798Leu	missense_variant	Exon 14 of 23		NP_001119603.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
POLG	ENST00000268124.11 link	c.2392A>C	p.Ile798Leu	missense_variant	Exon 14 of 23	1	NM_002693.3	ENSP00000268124.5

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152126

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000654

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:

0.00000398

AC:

AN:

251408

AF XY:

0.00

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 FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000880

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

Cov.:

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152126

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74308

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41434

American (AMR)

AF:

0.0000654

AC:

AN:

15280

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5186

South Asian (SAS)

AF:

0.00

AC:

AN:

4824

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10598

Middle Eastern (MID)

AF:

0.00

AC:

AN:

314

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68018

Other (OTH)

AF:

0.00

AC:

AN:

2090

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

Genome 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

Alfa

AF:

0.00

Hom.:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Uncertain:1

Feb 11, 2019

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Not observed in large population cohorts (Lek et al., 2016); In silico analysis, which includes protein predictors and evolutionary conservation, supports that this variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge

Progressive sclerosing poliodystrophy

Uncertain:1

Jul 25, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces isoleucine, which is neutral and non-polar, with leucine, which is neutral and non-polar, at codon 798 of the POLG protein (p.Ile798Leu). 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: 206464). Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated. 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.

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.22

BayesDel_addAF

Uncertain

0.16

BayesDel_noAF

Uncertain

-0.010

CADD

Benign

(source)

DANN

Benign

0.95

DEOGEN2

Uncertain

0.54

D;D

Eigen

Benign

-0.21

Eigen_PC

Benign

-0.071

FATHMM_MKL

Uncertain

0.92

LIST_S2

Benign

0.0

.;D

M_CAP

Uncertain

0.087

MetaRNN

Benign

0.37

T;T

MetaSVM

Uncertain

0.48

MutationAssessor

Benign

0.95

L;L

PhyloP100

3.2

PrimateAI

Uncertain

0.72

PROVEAN

Benign

-0.25

N;N

REVEL

Uncertain

0.40

Sift

Benign

0.49

T;T

Sift4G

Benign

0.61

T;T

Vest4

0.38

ClinPred

0.30

GERP RS

2.8

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.19

gMVP

0.72

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

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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