rs2307437

Variant summary

Our verdict is Likely benign. The variant received -5 ACMG points: 0P and 5B. BP4_StrongBP6

The NM_002693.3(POLG):​c.970C>T​(p.Pro324Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000509 in 1,613,522 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 17/22 in silico tools predict a benign 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. P324T) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.00043 ( 0 hom., cov: 33)
Exomes 𝑓: 0.00052 ( 0 hom. )

Consequence

POLG
NM_002693.3 missense

Scores

1
18

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:11B:7

Conservation

PhyloP100: 1.22

Publications

5 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

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -5 ACMG points.

BP4
Computational evidence support a benign effect (MetaRNN=0.025510073).
BP6
Variant 15-89328996-G-A is Benign according to our data. Variant chr15-89328996-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 21320.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
POLGNM_002693.3 linkc.970C>T p.Pro324Ser missense_variant Exon 4 of 23 ENST00000268124.11 NP_002684.1 P54098E5KNU5
POLGNM_001126131.2 linkc.970C>T p.Pro324Ser missense_variant Exon 4 of 23 NP_001119603.1 P54098E5KNU5

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
POLGENST00000268124.11 linkc.970C>T p.Pro324Ser missense_variant Exon 4 of 23 1 NM_002693.3 ENSP00000268124.5 P54098

Frequencies

GnomAD3 genomes
AF:
0.000434
AC:
66
AN:
152226
Hom.:
0
Cov.:
33
show subpopulations
Gnomad AFR
AF:
0.000145
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:
0.000867
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.000288
AC:
72
AN:
250106
AF XY:
0.000281
show subpopulations
Gnomad AFR exome
AF:
0.0000618
Gnomad AMR exome
AF:
0.0000289
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.0000924
Gnomad NFE exome
AF:
0.000595
Gnomad OTH exome
AF:
0.000164
GnomAD4 exome
AF:
0.000517
AC:
756
AN:
1461296
Hom.:
0
Cov.:
33
AF XY:
0.000508
AC XY:
369
AN XY:
726916
show subpopulations
African (AFR)
AF:
0.000179
AC:
6
AN:
33464
American (AMR)
AF:
0.0000447
AC:
2
AN:
44724
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26136
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39700
South Asian (SAS)
AF:
0.0000116
AC:
1
AN:
86220
European-Finnish (FIN)
AF:
0.000150
AC:
8
AN:
53312
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5390
European-Non Finnish (NFE)
AF:
0.000632
AC:
703
AN:
1112006
Other (OTH)
AF:
0.000597
AC:
36
AN:
60344
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.452
Heterozygous variant carriers
0
45
91
136
182
227
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
28
56
84
112
140
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
GnomAD4 genome
AF:
0.000434
AC:
66
AN:
152226
Hom.:
0
Cov.:
33
AF XY:
0.000524
AC XY:
39
AN XY:
74368
show subpopulations
African (AFR)
AF:
0.000145
AC:
6
AN:
41464
American (AMR)
AF:
0.0000654
AC:
1
AN:
15284
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5198
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4824
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10630
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
314
European-Non Finnish (NFE)
AF:
0.000867
AC:
59
AN:
68038
Other (OTH)
AF:
0.00
AC:
0
AN:
2090
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.485
Heterozygous variant carriers
0
4
8
12
16
20
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome Het
Variant carriers
0
2
4
6
8
10
<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:
0.000688
Hom.:
0
Bravo
AF:
0.000393
TwinsUK
AF:
0.000539
AC:
2
ALSPAC
AF:
0.000778
AC:
3
ESP6500AA
AF:
0.00
AC:
0
ESP6500EA
AF:
0.000814
AC:
7
ExAC
AF:
0.000305
AC:
37
EpiCase
AF:
0.000763
EpiControl
AF:
0.000356

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Uncertain:11Benign:7
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

not provided Uncertain:5Benign:3
-
Genome Diagnostics Laboratory, University Medical Center Utrecht
Significance:Likely benign
Review Status:no assertion criteria provided
Collection Method:clinical testing

- -

-
Diagnostic Laboratory, Department of Genetics, University Medical Center Groningen
Significance:Likely benign
Review Status:no assertion criteria provided
Collection Method:clinical testing

- -

Aug 01, 2019
Revvity Omics, Revvity
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Jan 04, 2021
Greenwood Genetic Center Diagnostic Laboratories, Greenwood Genetic Center
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

No ACMG evidence could be applied applied -

Jul 10, 2024
Athena Diagnostics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

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) Polyphen and MutationTaster predict this amino acid change may be benign. -

May 02, 2017
Eurofins Ntd Llc (ga)
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Jan 17, 2020
Mayo Clinic Laboratories, Mayo Clinic
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Sep 01, 2024
CeGaT Center for Human Genetics Tuebingen
Significance:Likely benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

POLG: BP4 -

not specified Uncertain:1Benign:2
Nov 11, 2013
GeneDx
Significance:Benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -

-
Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center
Significance:Benign
Review Status:no assertion criteria provided
Collection Method:clinical testing

- -

Oct 17, 2024
Women's Health and Genetics/Laboratory Corporation of America, LabCorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Variant summary: POLG c.970C>T (p.Pro324Ser) results in a non-conservative amino acid change located in the DNA mitochondrial polymerase, exonuclease domain (IPR041336) of the encoded protein sequence. Four of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 0.00029 in 250106 control chromosomes. This frequency is not significantly higher than estimated for a pathogenic variant in POLG causing POLG-Related Spectrum Disorders, allowing no conclusion about variant significance. To our knowledge, no occurrence of c.970C>T in individuals affected with POLG-Related Spectrum Disorders and no experimental evidence demonstrating its impact on protein function have been reported. ClinVar contains an entry for this variant (Variation ID: 21320). Based on the evidence outlined above, the variant was classified as uncertain significance. -

Progressive sclerosing poliodystrophy Benign:2
Jan 23, 2025
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Likely benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Oct 01, 2018
Wong Mito Lab, Molecular and Human Genetics, Baylor College of Medicine
Significance:Benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The NM_002693.2:c.970C>T (NP_002684.1:p.Pro324Ser) [GRCH38: NC_000015.10:g.89328996G>A] variant in POLG gene is interpretated to be a Benign based on ACMG guidelines (PMID: 25741868). This variant meets the following evidence codes reported in the ACMG-guideline. BS1:The minor allele frequency of this allele is high for Mitochondrial DNA depletion syndrome 4A (Alpers type). BS2:Observation of the variant in controls is inconsistent with penetrance of Mitochondrial DNA depletion syndrome 4A (Alpers type). BP4:Computational evidence/predictors indicate no impact on the POLG structure, function, or protein-protein interaction. Based on the evidence criteria codes applied, the variant is suggested to be Benign. -

Charcot-Marie-Tooth disease Uncertain:1
Oct 17, 2019
Cambridge Genomics Laboratory, East Genomic Laboratory Hub, NHS Genomic Medicine Service
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

POLG-Related Spectrum Disorders Uncertain:1
Jan 12, 2018
Illumina Laboratory Services, Illumina
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Inborn genetic diseases Uncertain:1
Jun 09, 2025
Ambry Genetics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Unlikely to be causative of AD POLG-related progressive external ophthalmoplegia. Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Hereditary spastic paraplegia Uncertain:1
Jun 01, 2019
Genome Diagnostics Laboratory, The Hospital for Sick Children
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

POLG-related disorder Uncertain:1
Jul 26, 2024
PreventionGenetics, part of Exact Sciences
Significance:Uncertain significance
Review Status:no assertion criteria provided
Collection Method:clinical testing

The POLG c.970C>T variant is predicted to result in the amino acid substitution p.Pro324Ser. This variant has been reported in the heterozygous state in individuals with suspected POLG-deficiency and interpreted as uncertain significance (Tang et al. 2018. PubMed ID: 21880868). This variant is reported in 0.059% of alleles in individuals of European (Non-Finnish) descent in gnomAD, which may be too common to be a primary cause of disease. Although we suspect that this variant may be benign, at this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
0.073
BayesDel_addAF
Benign
-0.30
T
BayesDel_noAF
Benign
-0.31
CADD
Benign
9.3
DANN
Benign
0.21
DEOGEN2
Benign
0.17
T;T
Eigen
Benign
-1.5
Eigen_PC
Benign
-1.3
FATHMM_MKL
Uncertain
0.82
D
LIST_S2
Benign
0.29
.;T
M_CAP
Benign
0.039
D
MetaRNN
Benign
0.026
T;T
MetaSVM
Benign
-0.65
T
MutationAssessor
Benign
-0.26
N;N
PhyloP100
1.2
PrimateAI
Benign
0.20
T
PROVEAN
Benign
0.65
N;N
REVEL
Benign
0.29
Sift
Benign
0.85
T;T
Sift4G
Benign
0.75
T;T
Polyphen
0.0010
B;B
Vest4
0.15
MVP
0.58
MPC
0.16
ClinPred
0.86
D
GERP RS
-1.1
PromoterAI
-0.0082
Neutral
RBP_binding_hub_radar
0.0
RBP_regulation_power_radar
1.7
Varity_R
0.016
gMVP
0.28
Mutation Taster
=96/4
polymorphism

Splicing

Name
Calibrated prediction
Score
Prediction
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

Other links and lift over

dbSNP: rs2307437; hg19: chr15-89872227; API