rs750928338

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PP3_Moderate

The NM_002693.3(POLG):​c.602T>G​(p.Val201Gly) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000117 in 1,540,028 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. V201F) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 34)
Exomes 𝑓: 0.000012 ( 0 hom. )

Consequence

POLG
NM_002693.3 missense

Scores

14
4
1

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:2

Conservation

PhyloP100: 7.33

Publications

0 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]
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]

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

PP3
MetaRNN computational evidence supports a deleterious effect, 0.919

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
POLGNM_002693.3 linkc.602T>G p.Val201Gly missense_variant Exon 2 of 23 ENST00000268124.11 NP_002684.1
POLGARFNM_001430120.1 linkc.657T>G p.Gly219Gly synonymous_variant Exon 1 of 2 ENST00000706918.1 NP_001417049.1
POLGNM_001126131.2 linkc.602T>G p.Val201Gly missense_variant Exon 2 of 23 NP_001119603.1

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
POLGENST00000268124.11 linkc.602T>G p.Val201Gly missense_variant Exon 2 of 23 1 NM_002693.3 ENSP00000268124.5
POLGARFENST00000706918.1 linkc.657T>G p.Gly219Gly synonymous_variant Exon 1 of 2 NM_001430120.1 ENSP00000516626.1

Frequencies

GnomAD3 genomes
AF:
0.0000132
AC:
2
AN:
151970
Hom.:
0
Cov.:
34
show subpopulations
Gnomad AFR
AF:
0.0000242
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.00
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:
0.0000147
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.00000526
AC:
1
AN:
190104
AF XY:
0.00000974
show subpopulations
Gnomad AFR exome
AF:
0.0000680
Gnomad AMR exome
AF:
0.00
Gnomad ASJ exome
AF:
0.00
Gnomad EAS 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:
0.0000115
AC:
16
AN:
1388058
Hom.:
0
Cov.:
32
AF XY:
0.0000117
AC XY:
8
AN XY:
682232
show subpopulations
African (AFR)
AF:
0.0000323
AC:
1
AN:
30952
American (AMR)
AF:
0.00
AC:
0
AN:
33474
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
21578
East Asian (EAS)
AF:
0.00
AC:
0
AN:
38824
South Asian (SAS)
AF:
0.00
AC:
0
AN:
75666
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
49816
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5436
European-Non Finnish (NFE)
AF:
0.0000140
AC:
15
AN:
1075224
Other (OTH)
AF:
0.00
AC:
0
AN:
57088
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.484
Heterozygous variant carriers
0
1
3
4
6
7
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome 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
GnomAD4 genome
AF:
0.0000132
AC:
2
AN:
151970
Hom.:
0
Cov.:
34
AF XY:
0.00
AC XY:
0
AN XY:
74232
show subpopulations
African (AFR)
AF:
0.0000242
AC:
1
AN:
41338
American (AMR)
AF:
0.00
AC:
0
AN:
15282
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3468
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5178
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4818
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10594
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.0000147
AC:
1
AN:
67976
Other (OTH)
AF:
0.00
AC:
0
AN:
2088
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.400
Heterozygous variant carriers
0
0
1
1
2
2
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:
0.0000605
Hom.:
0
Bravo
AF:
0.0000378
ExAC
AF:
0.00000826
AC:
1

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:2
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

not provided Uncertain:1
Dec 19, 2023
GeneDx
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

Progressive sclerosing poliodystrophy Uncertain:1
Nov 23, 2024
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces valine, which is neutral and non-polar, with glycine, which is neutral and non-polar, at codon 201 of the POLG protein (p.Val201Gly). This variant is present in population databases (rs750928338, 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: 458720). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt POLG protein function with a positive predictive value of 95%. 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
Pathogenic
0.62
BayesDel_addAF
Pathogenic
0.41
D
BayesDel_noAF
Pathogenic
0.53
CADD
Pathogenic
28
DANN
Uncertain
1.0
DEOGEN2
Pathogenic
0.88
D;D
Eigen
Pathogenic
0.80
Eigen_PC
Pathogenic
0.71
FATHMM_MKL
Pathogenic
0.98
D
LIST_S2
Uncertain
0.86
.;D
M_CAP
Pathogenic
0.60
D
MetaRNN
Pathogenic
0.92
D;D
MetaSVM
Pathogenic
1.0
D
MutationAssessor
Pathogenic
3.8
H;H
PhyloP100
7.3
PrimateAI
Uncertain
0.63
T
PROVEAN
Pathogenic
-5.3
D;D
REVEL
Pathogenic
0.90
Sift
Uncertain
0.0010
D;D
Sift4G
Pathogenic
0.0010
D;D
Polyphen
1.0
D;D
Vest4
0.66
MVP
1.0
MPC
0.75
ClinPred
0.99
D
GERP RS
4.6
PromoterAI
-0.014
Neutral
Varity_R
0.92
gMVP
0.91
Mutation Taster
=14/86
disease causing

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

Other links and lift over

dbSNP: rs750928338; hg19: chr15-89876384; API