rs758454871

Positions:

chr15-89333268-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM1PP3_Moderate

The NM_002693.3(POLG):c.487C>T(p.Pro163Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000128 in 1,561,606 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic 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. P163L) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000033 ( 0 hom., cov: 34)

Exomes 𝑓: 0.000011 ( 0 hom. )

Consequence

POLG
NM_002693.3 missense

Scores

Clinical Significance

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

Conservation

PhyloP100: 7.57

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 Uncertain_significance. Variant got 4 ACMG points.

PM1

In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 10 uncertain in NM_002693.3

PP3

MetaRNN computational evidence supports a deleterious effect, 0.86

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE
POLG	NM_002693.3 linkuse as main transcript	c.487C>T	p.Pro163Ser	missense_variant	2/23	ENST00000268124.11
POLGARF	NM_001406557.1 linkuse as main transcript	c.542C>T	p.Ala181Val	missense_variant	2/23
POLG	NM_001126131.2 linkuse as main transcript	c.487C>T	p.Pro163Ser	missense_variant	2/23

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
POLG	ENST00000268124.11 linkuse as main transcript	c.487C>T	p.Pro163Ser	missense_variant	2/23	1	NM_002693.3	P1
POLGARF	ENST00000706918.1 linkuse as main transcript	c.542C>T	p.Ala181Val	missense_variant	1/2			P1

Frequencies

GnomAD3 genomes

AF:

0.0000328

AC:

AN:

152240

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000327

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000291

AC:

AN:

171530

Hom.:

AF XY:

0.0000425

AC XY:

AN XY:

94192

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.000110

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000772

Gnomad SAS exome

AF:

0.0000402

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000106

AC:

AN:

1409366

Hom.:

Cov.:

AF XY:

0.0000129

AC XY:

AN XY:

696018

show subpopulations

Gnomad4 AFR exome

AF:

0.0000313

Gnomad4 AMR exome

AF:

0.000129

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000542

Gnomad4 SAS exome

AF:

0.0000123

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000553

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000328

AC:

AN:

152240

Hom.:

Cov.:

AF XY:

0.0000538

AC XY:

AN XY:

74370

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.000327

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000316

Hom.:

Bravo

AF:

0.0000491

ExAC

AF:

0.0000256

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Jul 27, 2023

Variant summary: POLG c.487C>T (p.Pro163Ser) results in a non-conservative amino acid change located in the DNA mitochondrial polymerase, exonuclease domain (IPR041336) of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 2.9e-05 in 171530 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.487C>T has been reported in the literature in an individual affected with POLG Related condition (example: Woodbridge_2013). These data do not allow any conclusion about variant significance. One publication reports experimental evidence evaluating an impact on protein function, however, does not allow convincing conclusions about the variant effect (example: Kasahara_2017). The following publications have been ascertained in the context of this evaluation (PMID: 27987238, 22647225). Two submitters have cited clinical-significance assessments for this variant to ClinVar after 2014. All submitters classified the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Athena Diagnostics

Jun 28, 2018

- -

Progressive sclerosing poliodystrophy

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Sep 17, 2023

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 expected to disrupt POLG protein function. 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. ClinVar contains an entry for this variant (Variation ID: 586365). This missense change has been observed in individual(s) with chronic progressiveexternal ophthalmoplegia, seizure, neuropathy, and ataxia (PMID: 22647225). This variant is present in population databases (rs758454871, gnomAD 0.01%). This sequence change replaces proline, which is neutral and non-polar, with serine, which is neutral and polar, at codon 163 of the POLG protein (p.Pro163Ser). -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.30

BayesDel_addAF

Pathogenic

0.28

BayesDel_noAF

Pathogenic

0.38

CADD

Uncertain

DANN

Pathogenic

1.0

Eigen

Pathogenic

0.73

Eigen_PC

Uncertain

0.64

FATHMM_MKL

Pathogenic

0.98

M_CAP

Pathogenic

0.46

MetaRNN

Pathogenic

0.86

MutationTaster

Benign

1.0

D;D

ClinPred

0.99

GERP RS

3.9

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.2

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