rs377390914

chr15-89321135-G-A

Variant summary

Our verdict is Likely benign. Variant got -6 ACMG points: 0P and 6B. BP4_Strong BP6 BP7

The NM_002693.3(POLG):c.2724C>T(p.Ala908=) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000141 in 1,614,104 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. A908A) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.000079 (0 hom., cov: 33)
  • Exomes 𝑓: 0.00015 (0 hom.)
• Consequence: POLG NM_002693.3 synonymous
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3 B:5
• Conservation: PhyloP100: -2.71

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:):

ACMG classification

Verdict is Likely_benign. Variant got -6 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.63).
• BP6: Variant 15-89321135-G-A is Benign according to our data. Variant chr15-89321135-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 194733.We mark this variant Likely_benign, oryginal submissions are: {Uncertain_significance=3, Likely_benign=3, Benign=1}.
• BP7: Synonymous conserved (PhyloP=-2.71 with no splicing effect.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
POLG	NM_002693.3	c.2724C>T	p.Ala908=	synonymous_variant	17/23	ENST00000268124.11
POLGARF	NM_001406557.1	c.*1996C>T		3_prime_UTR_variant	17/23
POLG	NM_001126131.2	c.2724C>T	p.Ala908=	synonymous_variant	17/23

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
POLG	ENST00000268124.11	c.2724C>T	p.Ala908=	synonymous_variant	17/23	1	NM_002693.3	P1

Frequencies

GnomAD3 genomes AF: 0.0000788 AC: 12 AN: 152226 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000482

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.000192

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.0000941

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.000118

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.000111 AC: 28 AN: 251200 Hom.: 0 AF XY: 0.0000810 AC XY: 11 AN XY: 135780

Gnomad AFR exome AF: 0.000123

Gnomad AMR exome AF: 0.0000289

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000544

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.000211

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.000148 AC: 216 AN: 1461878 Hom.: 0 Cov.: 35 AF XY: 0.000150 AC XY: 109 AN XY: 727242

Gnomad4 AFR exome AF: 0.0000896

Gnomad4 AMR exome AF: 0.0000224

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000252

Gnomad4 SAS exome AF: 0.0000348

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.000183

Gnomad4 OTH exome AF: 0.0000828

GnomAD4 genome AF: 0.0000788 AC: 12 AN: 152226 Hom.: 0 Cov.: 33 AF XY: 0.0000941 AC XY: 7 AN XY: 74362

Gnomad4 AFR AF: 0.0000482

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.000192

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.0000941

Gnomad4 NFE AF: 0.000118

Gnomad4 OTH AF: 0.00

Alfa AF: 0.000132 Hom.: 0

Bravo AF: 0.0000869

EpiCase AF: 0.000327

EpiControl AF: 0.000119

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3 Benign:5

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Uncertain:1 Benign:2

Uncertain significance, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Jan 04, 2015	- -
Likely benign, criteria provided, single submitter	clinical testing	Athena Diagnostics	May 06, 2020	- -
Likely benign, no assertion criteria provided	clinical testing	Mayo Clinic Laboratories, Mayo Clinic	Feb 25, 2016	- -

not specified Uncertain:1 Benign:1

Uncertain significance, criteria provided, single submitter	clinical testing	Genetic Services Laboratory, University of Chicago	Nov 13, 2014	- -
Benign, criteria provided, single submitter	clinical testing	GeneDx	Sep 10, 2014	This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -

POLG-Related Spectrum Disorders Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 13, 2018

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 Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Jan 19, 2018

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Progressive sclerosing poliodystrophy Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Invitae

Jan 26, 2024

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.63
Cadd	Benign	1.7
Dann	Benign	0.83
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

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: rs377390914; hg19: chr15-89864366;