rs551708243

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 1P and 0B. PP3

The NM_002693.3(POLG):​c.3098C>T​(p.Ala1033Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00022 in 1,614,122 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. 14/24 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. A1033K) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.00034 ( 1 hom., cov: 32)
Exomes 𝑓: 0.00021 ( 0 hom. )

Consequence

POLG
NM_002693.3 missense

Scores

2
17

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:11B:2

Conservation

PhyloP100: 0.309

Publications

2 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: Uncertain_significance. The variant received 1 ACMG points.

PP3
Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
POLGNM_002693.3 linkc.3098C>T p.Ala1033Val missense_variant Exon 19 of 23 ENST00000268124.11 NP_002684.1
POLGNM_001126131.2 linkc.3098C>T p.Ala1033Val missense_variant Exon 19 of 23 NP_001119603.1

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
POLGENST00000268124.11 linkc.3098C>T p.Ala1033Val missense_variant Exon 19 of 23 1 NM_002693.3 ENSP00000268124.5

Frequencies

GnomAD3 genomes
AF:
0.000342
AC:
52
AN:
152118
Hom.:
1
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.0000966
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.00124
Gnomad ASJ
AF:
0.00173
Gnomad EAS
AF:
0.00
Gnomad SAS
AF:
0.00
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00949
Gnomad NFE
AF:
0.000206
Gnomad OTH
AF:
0.00287
GnomAD2 exomes
AF:
0.000255
AC:
64
AN:
251460
AF XY:
0.000243
show subpopulations
Gnomad AFR exome
AF:
0.0000615
Gnomad AMR exome
AF:
0.000578
Gnomad ASJ exome
AF:
0.00119
Gnomad EAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.000185
Gnomad OTH exome
AF:
0.000489
GnomAD4 exome
AF:
0.000207
AC:
303
AN:
1461886
Hom.:
0
Cov.:
34
AF XY:
0.000202
AC XY:
147
AN XY:
727244
show subpopulations
African (AFR)
AF:
0.000119
AC:
4
AN:
33480
American (AMR)
AF:
0.000581
AC:
26
AN:
44722
Ashkenazi Jewish (ASJ)
AF:
0.00111
AC:
29
AN:
26136
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39700
South Asian (SAS)
AF:
0.000174
AC:
15
AN:
86258
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53416
Middle Eastern (MID)
AF:
0.00381
AC:
22
AN:
5768
European-Non Finnish (NFE)
AF:
0.000157
AC:
175
AN:
1112010
Other (OTH)
AF:
0.000530
AC:
32
AN:
60396
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.471
Heterozygous variant carriers
0
21
42
62
83
104
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
10
20
30
40
50
<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:
0.000342
AC:
52
AN:
152236
Hom.:
1
Cov.:
32
AF XY:
0.000443
AC XY:
33
AN XY:
74442
show subpopulations
African (AFR)
AF:
0.0000963
AC:
4
AN:
41538
American (AMR)
AF:
0.00124
AC:
19
AN:
15302
Ashkenazi Jewish (ASJ)
AF:
0.00173
AC:
6
AN:
3470
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5174
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4822
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10606
Middle Eastern (MID)
AF:
0.0102
AC:
3
AN:
294
European-Non Finnish (NFE)
AF:
0.000206
AC:
14
AN:
68008
Other (OTH)
AF:
0.00284
AC:
6
AN:
2112
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.502
Heterozygous variant carriers
0
3
6
8
11
14
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome Het
Genome Hom
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:
0.000262
Hom.:
0
Bravo
AF:
0.000404
ExAC
AF:
0.000173
AC:
21
EpiCase
AF:
0.000273
EpiControl
AF:
0.000415

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Uncertain:11Benign:2
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

not provided Uncertain:4Benign:1
Oct 26, 2020
GeneDx
Significance:Likely benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This variant is associated with the following publications: (PMID: 21880868, 30290626) -

Oct 16, 2017
Eurofins Ntd Llc (ga)
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Jul 31, 2020
Mayo Clinic Laboratories, Mayo Clinic
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Oct 25, 2023
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) Computational tools predict that this variant is not damaging. -

Mar 21, 2022
Revvity Omics, Revvity
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Progressive sclerosing poliodystrophy Uncertain:1Benign:1
Feb 02, 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:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The NM_002693.2:c.3098C>T (NP_002684.1:p.Ala1033Val) [GRCH38: NC_000015.10:g.89319234G>A] variant in POLG gene is interpretated to be a Uncertain Significance based on ACMG guidelines (PMID: 25741868). This variant meets the following evidence codes reported in the ACMG-guideline. 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. PP3:Computational evidence/predictors indicate the variant has deleterious effect on POLG structure, function, or protein-protein interaction. Based on the evidence criteria codes applied, the variant is suggested to be Uncertain Significance. -

Progressive external ophthalmoplegia with mitochondrial DNA deletions, autosomal recessive 1 Uncertain:1
Sep 09, 2020
Baylor Genetics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This variant was determined to be of uncertain significance according to ACMG Guidelines, 2015 [PMID:25741868]. -

Progressive sclerosing poliodystrophy;C1834846:Progressive external ophthalmoplegia with mitochondrial DNA deletions, autosomal dominant 1;C1843851:Sensory ataxic neuropathy, dysarthria, and ophthalmoparesis;C3150914:Mitochondrial DNA depletion syndrome 4b;C4225153:Progressive external ophthalmoplegia with mitochondrial DNA deletions, autosomal recessive 1;C4551995:Mitochondrial DNA depletion syndrome 1 Uncertain:1
Oct 31, 2018
Fulgent Genetics, Fulgent Genetics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

POLG-Related Spectrum Disorders Uncertain:1
Jan 13, 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
Dec 09, 2024
Ambry Genetics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The c.3098C>T (p.A1033V) alteration is located in exon 19 (coding exon 18) of the POLG gene. This alteration results from a C to T substitution at nucleotide position 3098, causing the alanine (A) at amino acid position 1033 to be replaced by a valine (V). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Progressive external ophthalmoplegia with mitochondrial DNA deletions, autosomal dominant 1;C1843851:Sensory ataxic neuropathy, dysarthria, and ophthalmoparesis;C3150914:Mitochondrial DNA depletion syndrome 4b;C4225153:Progressive external ophthalmoplegia with mitochondrial DNA deletions, autosomal recessive 1;C4551995:Mitochondrial DNA depletion syndrome 1 Uncertain:1
Nov 08, 2022
Department of Pathology and Laboratory Medicine, Sinai Health System
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:research

- -

POLG-related disorder Uncertain:1
Aug 22, 2024
PreventionGenetics, part of Exact Sciences
Significance:Uncertain significance
Review Status:no assertion criteria provided
Collection Method:clinical testing

The POLG c.3098C>T variant is predicted to result in the amino acid substitution p.Ala1033Val. This variant has been reported in the compound heterozygous state along with a second variant in this gene in a individual with hypotonia, low set ears, and bilateral clubfeet (AlJabri et al. 2018. PubMed ID: 30290626) and found in the heterozygous condition another individual with encephalopathy, seizure, and abnormal MRI (Table S2, Tang et al. 2011. PubMed ID: 21880868). This variant is reported in 0.13% of alleles in individuals of Ashkenazi Jewish descent in gnomAD. 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
0.097
BayesDel_addAF
Benign
-0.20
T
BayesDel_noAF
Benign
-0.18
CADD
Benign
23
DANN
Benign
0.93
DEOGEN2
Uncertain
0.63
D;D
Eigen
Benign
-0.66
Eigen_PC
Benign
-0.52
FATHMM_MKL
Benign
0.50
N
LIST_S2
Benign
0.70
.;T
M_CAP
Benign
0.036
D
MetaRNN
Benign
0.053
T;T
MetaSVM
Benign
-0.29
T
MutationAssessor
Benign
0.90
L;L
PhyloP100
0.31
PrimateAI
Benign
0.22
T
PROVEAN
Benign
-0.24
N;N
REVEL
Uncertain
0.32
Sift
Benign
0.28
T;T
Sift4G
Benign
0.39
T;T
Polyphen
0.0010
B;B
Vest4
0.26
MVP
0.87
MPC
0.16
ClinPred
0.022
T
GERP RS
5.1
Varity_R
0.054
gMVP
0.49
Mutation Taster
=62/38
polymorphism

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.76
Details are displayed if max score is > 0.2
DS_DG_spliceai
0.76
Position offset: 2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

Other links and lift over

dbSNP: rs551708243; hg19: chr15-89862465; COSMIC: COSV51519611; COSMIC: COSV51519611; API