15-89333102-G-T

Position:

• chr15-89333102-G-T

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PVS1 PM2

The NM_002693.3(POLG):​c.653C>A​(p.Ser218*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 7.3e-7 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: POLG NM_002693.3 stop_gained
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.45

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]

POLGARF (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 10 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
POLG	NM_002693.3	c.653C>A	p.Ser218*	stop_gained	2/23	ENST00000268124.11	NP_002684.1
POLG	NM_001126131.2	c.653C>A	p.Ser218*	stop_gained	2/23		NP_001119603.1
POLGARF	NM_001406557.1	c.708C>A	p.Leu236Leu	synonymous_variant	2/23

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
POLG	ENST00000268124.11	c.653C>A	p.Ser218*	stop_gained	2/23	1	NM_002693.3	ENSP00000268124.5
POLGARF	ENST00000706918.1	c.708C>A	p.Leu236Leu	synonymous_variant	1/2			ENSP00000516626.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Data not reliable, filtered out with message: AS_VQSR AF: 7.33e-7 AC: 1 AN: 1364060 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 667448

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000141

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

CeGaT Center for Human Genetics Tuebingen

Jul 01, 2017

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.60	D
BayesDel_noAF	Pathogenic	0.44
CADD	Pathogenic	37
DANN	Uncertain	1.0
Eigen	Uncertain	0.58
Eigen_PC	Uncertain	0.40
FATHMM_MKL	Uncertain	0.82	D
Vest4		0.66
GERP RS		2.4
RBP_binding_hub_radar		0.92
RBP_regulation_power_radar		2.7

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

LitVar

Other links and lift over

dbSNP: rs1060500775; hg19: chr15-89876333;