rs368587966

Positions:

chr15-89321223-T-C

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM1PM5PP3_ModeratePP5

The NM_002693.3(POLG):c.2636A>G(p.Gln879Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000991 in 1,614,052 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. Q879H) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.000066 ( 0 hom., cov: 33)

Exomes 𝑓: 0.0000041 ( 0 hom. )

Consequence

POLG
NM_002693.3 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2U:2

Conservation

PhyloP100: 7.67

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_pathogenic. Variant got 7 ACMG points.

PM1

In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 13 uncertain in NM_002693.3

PM5

Other missense variant is known to change same aminoacid residue: Variant chrnull-null-null-null is described in UniProt as null.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.905

PP5

Variant 15-89321223-T-C is Pathogenic according to our data. Variant chr15-89321223-T-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 206532.We mark this variant Likely_pathogenic, oryginal submissions are: {Pathogenic=2, Uncertain_significance=2}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE
POLG	NM_002693.3 linkuse as main transcript	c.2636A>G	p.Gln879Arg	missense_variant	17/23	ENST00000268124.11
POLGARF	NM_001406557.1 linkuse as main transcript	c.*1908A>G		3_prime_UTR_variant	17/23
POLG	NM_001126131.2 linkuse as main transcript	c.2636A>G	p.Gln879Arg	missense_variant	17/23

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
POLG	ENST00000268124.11 linkuse as main transcript	c.2636A>G	p.Gln879Arg	missense_variant	17/23	1	NM_002693.3	P1

Frequencies

GnomAD3 genomes

AF:

0.0000657

AC:

AN:

152198

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000193

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000131

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:

0.0000159

AC:

AN:

251126

Hom.:

AF XY:

0.00000737

AC XY:

AN XY:

135740

show subpopulations

Gnomad AFR exome

AF:

0.0000616

Gnomad AMR exome

AF:

0.0000868

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS 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:

0.00000410

AC:

AN:

1461854

Hom.:

Cov.:

AF XY:

0.00000275

AC XY:

AN XY:

727226

show subpopulations

Gnomad4 AFR exome

AF:

0.0000597

Gnomad4 AMR exome

AF:

0.0000894

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000657

AC:

AN:

152198

Hom.:

Cov.:

AF XY:

0.0000538

AC XY:

AN XY:

74350

show subpopulations

Gnomad4 AFR

AF:

0.000193

Gnomad4 AMR

AF:

0.000131

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:

0.0000644

Hom.:

Bravo

AF:

0.0000642

ESP6500AA

AF:

0.000227

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.0000165

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:2Uncertain:2

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Pathogenic:1Uncertain:1

Uncertain significance, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Nov 20, 2017	- -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Mar 05, 2014	p.Gln879Arg (CAG>CGG): c.2636 A>G in exon 17 of the POLG gene (NM_002693.2). The Gln879Arg missense change has not been published as a mutation, nor has it been reported as a benign polymorphism to our knowledge. It was not observed in approximately 5,000 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. The Gln879Arg mutation is a non-conservative amino acid substitution, which is likely to impact secondary protein structure as these residues differ in polarity, charge, size and/or other properties. This substitution occurs at a position that is conserved across species in the polymerase domain of the protein and a different missense mutation at the same codon (Gln879His) was identified in a patient with hepatotoxicity and encephalopathy who had another disease-causing mutation on the other chromosome (Horvath et al., 2008; McFarland et al., 2008). Functional studies indicate that Gln879His moderately decreases the polymerase activity of the enzyme, confirming the functional importance of this position in the protein (Kasiviswanathan et al., 2009). The variant is found in INFANT-EPI,DEPLTN-MITOP,CHILD-EPI panel(s). -

Progressive sclerosing poliodystrophy

Pathogenic:1Uncertain:1

Pathogenic, 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.2636A>G (NP_002684.1:p.Gln879Arg) [GRCH38: NC_000015.10:g.89321223T>C] variant in POLG gene is interpretated to be a Pathogenic based on ACMG guidelines (PMID: 25741868). This variant meets the following evidence codes reported in the ACMG-guideline. PS1:This variation causes same amino-acid change as an established pathogenic variant. PM1:This variant is in mutational hot spot or a well-studied functional domain without benign variation. PM2:This variant is absent in key population databases. PP1:This variant is co-segregated with Mitochondrial DNA depletion syndrome 4A (Alpers type) in multiple affected family members. PP2:This is a missense variant in POLG with a low rate of benign and high rate of pathogenic missense variations. PP4:Patient's phenotype or family history is highly specific for POLG. Based on the evidence criteria codes applied, the variant is suggested to be Pathogenic. -
Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Dec 12, 2023	This sequence change replaces glutamine, which is neutral and polar, with arginine, which is basic and polar, at codon 879 of the POLG protein (p.Gln879Arg). This variant is present in population databases (rs368587966, gnomAD 0.02%). 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: 206532). 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) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on 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. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.49

BayesDel_addAF

Pathogenic

0.30

BayesDel_noAF

Pathogenic

0.38

CADD

Pathogenic

DANN

Uncertain

1.0

DEOGEN2

Uncertain

0.79

D;D

Eigen

Uncertain

0.61

Eigen_PC

Uncertain

0.63

FATHMM_MKL

Pathogenic

0.97

LIST_S2

Pathogenic

0.97

.;D

M_CAP

Uncertain

0.24

MetaRNN

Pathogenic

0.91

D;D

MetaSVM

Pathogenic

1.0

MutationAssessor

Benign

1.3

L;L

MutationTaster

Benign

1.0

D;D

PrimateAI

Uncertain

0.74

PROVEAN

Uncertain

-2.8

D;D

REVEL

Pathogenic

0.85

Sift

Benign

0.10

T;T

Sift4G

Benign

0.16

T;T

Polyphen

1.0

D;D

Vest4

0.89

MVP

0.97

MPC

0.68

ClinPred

0.78

GERP RS

5.2

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.8

Varity_R

0.72

gMVP

0.89

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