rs199759055

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 7P and 4B. PM5PP3_StrongPP5BS2

The NM_002693.3(POLG):​c.1156C>T​(p.Arg386Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000026 in 1,613,962 control chromosomes in the GnomAD database, including 2 homozygotes. 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. R386H) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 33)
Exomes 𝑓: 0.000027 ( 2 hom. )

Consequence

POLG
NM_002693.3 missense

Scores

8
10
1

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:6U:6

Conservation

PhyloP100: 3.05

Publications

7 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 3 ACMG points.

PM5
Other missense variant is known to change same aminoacid residue: Variant chr15-89328698-C-G is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 3578004.Status of the report is criteria_provided_single_submitter, 1 stars.
PP3
MetaRNN computational evidence supports a deleterious effect, 0.97
PP5
Variant 15-89328699-G-A is Pathogenic according to our data. Variant chr15-89328699-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 206589.
BS2
High Homozygotes in GnomAdExome4 at 2 AR,AD gene

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
POLGNM_002693.3 linkc.1156C>T p.Arg386Cys missense_variant Exon 5 of 23 ENST00000268124.11 NP_002684.1 P54098E5KNU5
POLGNM_001126131.2 linkc.1156C>T p.Arg386Cys missense_variant Exon 5 of 23 NP_001119603.1 P54098E5KNU5

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
POLGENST00000268124.11 linkc.1156C>T p.Arg386Cys missense_variant Exon 5 of 23 1 NM_002693.3 ENSP00000268124.5 P54098

Frequencies

GnomAD3 genomes
AF:
0.0000197
AC:
3
AN:
152176
Hom.:
0
Cov.:
33
show subpopulations
Gnomad AFR
AF:
0.0000241
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:
0.0000294
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.0000358
AC:
9
AN:
251406
AF XY:
0.0000442
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.0000289
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.0000352
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.0000267
AC:
39
AN:
1461786
Hom.:
2
Cov.:
33
AF XY:
0.0000275
AC XY:
20
AN XY:
727188
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33480
American (AMR)
AF:
0.0000224
AC:
1
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:
0.0000696
AC:
6
AN:
86254
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53324
Middle Eastern (MID)
AF:
0.00485
AC:
28
AN:
5768
European-Non Finnish (NFE)
AF:
0.00000270
AC:
3
AN:
1112004
Other (OTH)
AF:
0.0000166
AC:
1
AN:
60396
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.471
Heterozygous variant carriers
0
3
5
8
10
13
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Exome 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
GnomAD4 genome
AF:
0.0000197
AC:
3
AN:
152176
Hom.:
0
Cov.:
33
AF XY:
0.0000135
AC XY:
1
AN XY:
74344
show subpopulations
African (AFR)
AF:
0.0000241
AC:
1
AN:
41450
American (AMR)
AF:
0.00
AC:
0
AN:
15282
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3470
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5190
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4834
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10610
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.0000294
AC:
2
AN:
68026
Other (OTH)
AF:
0.00
AC:
0
AN:
2088
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.542
Heterozygous variant carriers
0
1
1
2
2
3
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:
0.0000240
Hom.:
1
Bravo
AF:
0.0000264
ESP6500AA
AF:
0.000227
AC:
1
ESP6500EA
AF:
0.000116
AC:
1
ExAC
AF:
0.0000576
AC:
7

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Pathogenic:6Uncertain:6
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

not provided Pathogenic:2Uncertain:2
Jun 26, 2024
GeneDx
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 32347949, 20837862) -

Jan 29, 2018
Eurofins Ntd Llc (ga)
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Apr 11, 2017
Center for Pediatric Genomic Medicine, Children's Mercy Hospital and Clinics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Sep 13, 2022
Revvity Omics, Revvity
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Progressive sclerosing poliodystrophy Pathogenic:2Uncertain:1
Oct 01, 2018
Wong Mito Lab, Molecular and Human Genetics, Baylor College of Medicine
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The NM_002693.2:c.1156C>T (NP_002684.1:p.Arg386Cys) [GRCH38: NC_000015.10:g.89328699G>A] variant in POLG gene is interpretated to be a Pathogenic based on ACMG guidelines (PMID: 25741868). This variant has been reported in PMID:20837862 . This variant meets the following evidence codes reported in the ACMG-guideline. PS3:Well established functional studies show a deleterious effect on POLG. PM2:This variant is absent in key population databases. PM3:Detected in trans with a pathogenic variant for Mitochondrial DNA depletion syndrome 4A (Alpers type) which is a recessive disorder. 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. -

Dec 16, 2024
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 386 of the POLG protein (p.Arg386Cys). This variant is present in population databases (rs199759055, gnomAD 0.01%). This missense change has been observed in individual(s) with autosomal recessive POLG-related conditions (PMID: 20837862). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 206589). 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 currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -

Jun 20, 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]. -

Mitochondrial DNA depletion syndrome 4b Uncertain:2
Oct 19, 2020
Victorian Clinical Genetics Services, Murdoch Childrens Research Institute
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as 3A-VUS. Following criteria are met: 0102 - Loss of function is a known mechanism of disease in this gene and is associated with POLG-related disorders. (I) 0108 - This gene is associated with both recessive and dominant disease (OMIM). (I) 0112 - The condition associated with this gene has incomplete penetrance (OMIM). (I) 0200 - Variant is predicted to result in a missense amino acid change from arginine to cysteine. (I) 0251 - This variant is heterozygous. (I) 0304 - Variant is present in gnomAD <0.01 for a recessive condition (9 heterozygotes, 0 homozygotes). (P) 0309 - An alternative amino acid change at the same position has been observed in gnomAD (1 heterozygotes, 0 homozygotes). (I) 0501 - Missense variant consistently predicted to be damaging by multiple in silico tools or highly conserved with a major amino acid change. (SP) 0600 - Variant is located in an annotated domain or motif DNA mitochondrial polymerase exonuclease domain; PDB). (I) 0704 - Another missense variant comparable to the one identified in this case has limited previous evidence for pathogenicity. A variant in the same codon resulting in a change to histidine has been reported in patients with Alpers syndrome as VUS (ClinVar, PMID: 20883824). Another change to proline has also been reported in patient with early onset epilepsy (PMID: 31164858). (P). (SP) 0808 - Previous reports of pathogenicity for this variant are conflicting. The variant has been previously reported as VUS (4x), likely pathogenic (1x) and pathogenic (1x) (ClinVar, PMID: 20837862). (I) 0905 - No published segregation evidence has been identified for this variant. (I) 1007 - No published functional evidence has been identified for this variant. (I) 1201 - Heterozygous variant detected in trans with a second pathogenic heterozygous variant (p.P587L/p.T25aI) in a recessive disease. (SP) 1206 - This variant has been shown to be paternally inherited (by trio analysis). (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -

Mar 26, 2024
Genomic Medicine Center of Excellence, King Faisal Specialist Hospital and Research Centre
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

POLG-related disorder Pathogenic:1
Apr 09, 2024
PreventionGenetics, part of Exact Sciences
Significance:Likely pathogenic
Review Status:no assertion criteria provided
Collection Method:clinical testing

The POLG c.1156C>T variant is predicted to result in the amino acid substitution p.Arg386Cys. This variant was previously reported in the compound heterozygous state with a pathogenic variant in a patient with isolated distal myopathy of the upper limbs and the variant was segregating with the disease in the family (Giordano et al. 2010. PubMed ID: 20837862). This variant is reported in 0.013% of alleles in individuals of South Asian descent in gnomAD. Alternative variants at the same codon p.Arg386Pro and p.Arg386His were observed in POLG related disorders (Demos et al. 2019. PubMed ID: 31164858, Table 2; Baruffini et al. 2010. PubMed ID: 20883824) and p.Arg386His variant was confirmed by functional study in yeast to be damaging (Baruffini et al. 2010. PubMed ID: 20883824). In summary, we interpret the c.Arg386Cys variant as likely pathogenic. -

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 Pathogenic:1
Apr 11, 2024
Fulgent Genetics, Fulgent Genetics
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Progressive sclerosing poliodystrophy;C1843851:Sensory ataxic neuropathy, dysarthria, and ophthalmoparesis;C3150914:Mitochondrial DNA depletion syndrome 4b Uncertain:1
Jun 19, 2017
Mayo Clinic Laboratories, Mayo Clinic
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Uncertain
0.35
BayesDel_addAF
Pathogenic
0.29
D
BayesDel_noAF
Pathogenic
0.42
CADD
Pathogenic
32
DANN
Pathogenic
1.0
DEOGEN2
Uncertain
0.79
D;D
Eigen
Uncertain
0.61
Eigen_PC
Uncertain
0.55
FATHMM_MKL
Uncertain
0.96
D
LIST_S2
Uncertain
0.96
.;D
M_CAP
Uncertain
0.28
D
MetaRNN
Pathogenic
0.97
D;D
MetaSVM
Pathogenic
0.90
D
MutationAssessor
Uncertain
2.4
M;M
PhyloP100
3.0
PrimateAI
Uncertain
0.61
T
PROVEAN
Pathogenic
-5.9
D;D
REVEL
Pathogenic
0.79
Sift
Pathogenic
0.0
D;D
Sift4G
Uncertain
0.0020
D;D
Polyphen
1.0
D;D
Vest4
0.92
MVP
0.97
MPC
0.77
ClinPred
0.95
D
GERP RS
3.5
PromoterAI
-0.069
Neutral
Varity_R
0.80
gMVP
0.73
Mutation Taster
=7/93
disease causing (ClinVar)

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: rs199759055; hg19: chr15-89871930; COSMIC: COSV51521284; COSMIC: COSV51521284; API