15-89333347-G-T

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 4P and 2B. PM1PM2BP4_Moderate

The NM_002693.3(POLG):c.408C>A(p.Asp136Glu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,252 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/22 in silico tools predict a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another nucleotide change resulting in the same amino acid substitution has been previously reported as Likely benign in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. D136Y) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 34)

Exomes 𝑓: 0.0 ( 0 hom. )

Failed GnomAD Quality Control

Consequence

POLG
NM_002693.3 missense

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 1.66

Publications

3 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 links:

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]

POLGARF links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

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

PM1

In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 12 uncertain in NM_002693.3

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.19692397).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
POLG	NM_002693.3 link	c.408C>A	p.Asp136Glu	missense_variant	Exon 2 of 23	ENST00000268124.11	NP_002684.1	P54098E5KNU5
POLG	NM_001126131.2 link	c.408C>A	p.Asp136Glu	missense_variant	Exon 2 of 23		NP_001119603.1	P54098E5KNU5
POLGARF	NM_001430120.1 link	c.463C>A	p.Pro155Thr	missense_variant	Exon 1 of 2		NP_001417049.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
POLG	ENST00000268124.11 link	c.408C>A	p.Asp136Glu	missense_variant	Exon 2 of 23	1	NM_002693.3	ENSP00000268124.5		P54098
POLGARF	ENST00000706918.1 link	c.463C>A	p.Pro155Thr	missense_variant	Exon 1 of 2			ENSP00000516626.1		A0A3B3IS91

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152252

Hom.:

Cov.:

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD4 exome

Data not reliable, filtered out with message: AC0

AF:

0.00

AC:

AN:

1415842

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

701130

African (AFR)

AF:

0.00

AC:

AN:

32316

American (AMR)

AF:

0.00

AC:

AN:

38830

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

25302

East Asian (EAS)

AF:

0.00

AC:

AN:

37096

South Asian (SAS)

AF:

0.00

AC:

AN:

82110

European-Finnish (FIN)

AF:

0.00

AC:

AN:

44950

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5674

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1090924

Other (OTH)

AF:

0.00

AC:

AN:

58640

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152252

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74392

show subpopulations

African (AFR)

AF:

0.0000241

AC:

AN:

41470

American (AMR)

AF:

0.00

AC:

AN:

15292

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5202

South Asian (SAS)

AF:

0.00

AC:

AN:

4836

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10632

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68030

Other (OTH)

AF:

0.00

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.575

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.00

Hom.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.30

BayesDel_addAF

Benign

-0.013

BayesDel_noAF

Benign

-0.26

CADD

Uncertain

(source)

DANN

Benign

0.86

DEOGEN2

Benign

0.25

T;T

Eigen

Benign

-0.29

Eigen_PC

Benign

-0.15

FATHMM_MKL

Uncertain

0.88

LIST_S2

Benign

0.61

.;T

M_CAP

Uncertain

0.17

MetaRNN

Benign

0.20

T;T

MetaSVM

Benign

-0.37

MutationAssessor

Benign

1.3

L;L

PhyloP100

1.7

PrimateAI

Uncertain

0.62

PROVEAN

Benign

0.080

N;N

REVEL

Benign

0.22

Sift

Benign

1.0

T;T

Sift4G

Benign

1.0

T;T

Polyphen

0.43

B;B

Vest4

0.35

MutPred

0.42

Gain of disorder (P = 0.2129);Gain of disorder (P = 0.2129);

MVP

0.88

MPC

0.16

ClinPred

0.30

GERP RS

3.1

PromoterAI

0.097

Neutral

(source)

Varity_R

0.20

gMVP

0.51

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Computational scores

Splicing

Publications

Other links and lift over