chr15-89330223-T-C

Position:

chr15-89330223-T-C

Variant summary

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

The NM_002693.3(POLG):c.713A>G(p.Gln238Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000291 in 1,613,366 control chromosomes in the GnomAD database, with no homozygous occurrence. 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 Uncertain significance (★).

Frequency

Genomes: 𝑓 0.000033 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000029 ( 0 hom. )

Consequence

POLG
NM_002693.3 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 2.24

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:56246): (POLG alternative reading frame) This gene uses the same transcript as the POLG gene but has a CUG start codon and an alternate reading frame that makes a 260 aa protein. This protein is distinct from POLG isoforms and may interact with P32 (also known as C1QBP), a mitochondrial matrix protein thought to be involved in the expression of mitochondrial genome-encoded proteins. POLGARF protein may bind P32 and sequester it in the nucleolus. Interestingly, some disease-causing mutations thought to be in POLG may instead be associated with POLGARF. [provided by RefSeq, May 2022]

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=0.2106702).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein
POLG	NM_002693.3 linkuse as main transcript	c.713A>G	p.Gln238Arg	missense_variant	3/23	ENST00000268124.11	NP_002684.1
POLGARF	NM_001406557.1 linkuse as main transcript	c.768A>G	p.Pro256=	synonymous_variant	3/23		NP_001393486.1
POLG	NM_001126131.2 linkuse as main transcript	c.713A>G	p.Gln238Arg	missense_variant	3/23		NP_001119603.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
POLG	ENST00000268124.11 linkuse as main transcript	c.713A>G	p.Gln238Arg	missense_variant	3/23	1	NM_002693.3	ENSP00000268124	P1
POLGARF	ENST00000706918.1 linkuse as main transcript	c.768A>G	p.Pro256=	synonymous_variant	2/2			ENSP00000516626	P1

Frequencies

GnomAD3 genomes

AF:

0.0000328

AC:

AN:

152250

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:

0.000192

Gnomad SAS

AF:

0.000207

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000441

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000200

AC:

AN:

250324

Hom.:

AF XY:

0.0000295

AC XY:

AN XY:

135552

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:

0.0000980

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000177

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000287

AC:

AN:

1460998

Hom.:

Cov.:

AF XY:

0.0000248

AC XY:

AN XY:

726830

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.000252

Gnomad4 SAS exome

AF:

0.0000464

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000243

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000328

AC:

AN:

152368

Hom.:

Cov.:

AF XY:

0.0000268

AC XY:

AN XY:

74502

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.000193

Gnomad4 SAS

AF:

0.000207

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000441

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000284

Hom.:

Bravo

AF:

0.0000113

ExAC

AF:

0.0000165

AC:

Asia WGS

AF:

0.000289

AC:

AN:

3478

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Progressive sclerosing poliodystrophy

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jun 29, 2023

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. Experimental studies have shown that this missense change does not substantially affect POLG function (PMID: 27987238). 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. ClinVar contains an entry for this variant (Variation ID: 948661). This variant has not been reported in the literature in individuals affected with POLG-related conditions. This variant is present in population databases (rs56410699, gnomAD 0.01%). This sequence change replaces glutamine, which is neutral and polar, with arginine, which is basic and polar, at codon 238 of the POLG protein (p.Gln238Arg). -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.061

BayesDel_addAF

Benign

-0.077

BayesDel_noAF

Benign

-0.15

CADD

Benign

DANN

Uncertain

0.99

DEOGEN2

Benign

0.34

T;T

Eigen

Benign

0.038

Eigen_PC

Benign

0.18

FATHMM_MKL

Uncertain

0.96

LIST_S2

Benign

0.66

.;T

M_CAP

Benign

0.057

MetaRNN

Benign

0.21

T;T

MetaSVM

Uncertain

0.10

MutationAssessor

Uncertain

2.1

M;M

MutationTaster

Benign

0.51

D;D

PrimateAI

Benign

0.38

PROVEAN

Benign

-1.0

N;N

REVEL

Benign

0.21

Sift

Benign

0.094

T;T

Sift4G

Benign

0.28

T;T

Polyphen

0.65

P;P

Vest4

0.19

MutPred

0.24

Gain of phosphorylation at S240 (P = 0.0772);Gain of phosphorylation at S240 (P = 0.0772);

MVP

0.85

MPC

0.16

ClinPred

0.15

GERP RS

4.6

Varity_R

0.17

gMVP

0.63

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