chr15-89321738-G-A

Position:

chr15-89321738-G-A

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM1PP3_Strong

The NM_002693.3(POLG):c.2596C>T(p.Arg866Trp) variant causes a missense, splice region change. The variant allele was found at a frequency of 0.0000255 in 1,608,114 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. 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. R866Q) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000025 ( 0 hom. )

Consequence

POLG
NM_002693.3 missense, splice_region

Scores

Splicing: ADA: 0.4836

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:5

Conservation

PhyloP100: 4.32

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 6 ACMG points.

PM1

In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 8 uncertain in NM_002693.3

PP3

MetaRNN computational evidence supports a deleterious effect, 0.947

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE
POLG	NM_002693.3 linkuse as main transcript	c.2596C>T	p.Arg866Trp	missense_variant, splice_region_variant	16/23	ENST00000268124.11
POLGARF	NM_001406557.1 linkuse as main transcript	c.*1868C>T		splice_region_variant, 3_prime_UTR_variant	16/23
POLG	NM_001126131.2 linkuse as main transcript	c.2596C>T	p.Arg866Trp	missense_variant, splice_region_variant	16/23

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
POLG	ENST00000268124.11 linkuse as main transcript	c.2596C>T	p.Arg866Trp	missense_variant, splice_region_variant	16/23	1	NM_002693.3	P1

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

152158

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000654

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.000193

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

GnomAD3 exomes

AF:

0.0000159

AC:

AN:

251350

Hom.:

AF XY:

0.0000221

AC XY:

AN XY:

135866

show subpopulations

Gnomad AFR exome

AF:

0.0000615

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000544

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000176

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000254

AC:

AN:

1455956

Hom.:

Cov.:

AF XY:

0.0000248

AC XY:

AN XY:

724692

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000252

Gnomad4 SAS exome

AF:

0.0000232

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000289

Gnomad4 OTH exome

AF:

0.0000332

GnomAD4 genome

AF:

0.0000263

AC:

AN:

152158

Hom.:

Cov.:

AF XY:

0.0000404

AC XY:

AN XY:

74332

show subpopulations

Gnomad4 AFR

AF:

0.0000241

Gnomad4 AMR

AF:

0.0000654

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.000193

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000147

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000508

Hom.:

Bravo

AF:

0.0000227

ExAC

AF:

0.0000165

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:5

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Uncertain:3

Uncertain significance, criteria provided, single submitter	clinical testing	Mayo Clinic Laboratories, Mayo Clinic	Jan 17, 2020	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Athena Diagnostics	May 19, 2023	Available data are insufficient to determine the clinical significance of the variant at this time. The frequency of this variant in the general population is uninformative in assessment of its pathogenicity (http://gnomad.broadinstitute.org). Computational tools predict that this variant is damaging. -
Uncertain significance, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Jun 08, 2017	- -

Inborn genetic diseases

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Apr 23, 2018

The p.R866W variant (also known as c.2596C>T), located in coding exon 15 of the POLG gene, results from a C to T substitution at nucleotide position 2596. The arginine at codon 866 is replaced by tryptophan, an amino acid with dissimilar properties. In one study, this alteration was detected in 2/796 Japanese individuals with bipolar disorder and in 1/767 controls (Kasahara T et al. Psychiatry Clin. Neurosci., 2017 Aug;71:518-529). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Progressive sclerosing poliodystrophy

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Oct 13, 2022

This sequence change replaces arginine, which is basic and polar, with tryptophan, which is neutral and slightly polar, at codon 866 of the POLG protein (p.Arg866Trp). This variant is present in population databases (rs748777396, gnomAD 0.007%). 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: 502515). Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). 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

0.31

BayesDel_addAF

Pathogenic

0.37

BayesDel_noAF

Pathogenic

0.48

CADD

Pathogenic

DANN

Pathogenic

1.0

DEOGEN2

Pathogenic

0.95

D;D

Eigen

Uncertain

0.57

Eigen_PC

Uncertain

0.51

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Pathogenic

1.0

.;D

M_CAP

Pathogenic

0.33

MetaRNN

Pathogenic

0.95

D;D

MetaSVM

Pathogenic

1.1

MutationAssessor

Uncertain

2.3

M;M

MutationTaster

Benign

1.0

D;D

PrimateAI

Pathogenic

0.81

PROVEAN

Uncertain

-4.3

D;D

REVEL

Pathogenic

0.81

Sift

Uncertain

0.0030

D;D

Sift4G

Uncertain

0.0070

D;D

Polyphen

1.0

D;D

Vest4

0.94

MVP

0.98

MPC

0.67

ClinPred

0.97

GERP RS

3.1

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.0

Varity_R

0.66

gMVP

0.83

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Benign

0.48

dbscSNV1_RF

Benign

0.64

SpliceAI score (max)

0.010

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