rs199751339

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 0P and 0B.

The NM_002693.3(POLG):​c.3650C>T​(p.Ala1217Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000849 in 1,612,804 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. A1217A) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000085 ( 0 hom., cov: 32)
Exomes 𝑓: 0.000085 ( 0 hom. )

Consequence

POLG
NM_002693.3 missense

Scores

9
9
1

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:9

Conservation

PhyloP100: 9.56
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]
FANCI (HGNC:25568): (FA complementation group I) The Fanconi anemia complementation group (FANC) currently includes FANCA, FANCB, FANCC, FANCD1 (also called BRCA2), FANCD2, FANCE, FANCF, FANCG, FANCI, FANCJ (also called BRIP1), FANCL, FANCM and FANCN (also called PALB2). The previously defined group FANCH is the same as FANCA. Fanconi anemia is a genetically heterogeneous recessive disorder characterized by cytogenetic instability, hypersensitivity to DNA crosslinking agents, increased chromosomal breakage, and defective DNA repair. The members of the Fanconi anemia complementation group do not share sequence similarity; they are related by their assembly into a common nuclear protein complex. This gene encodes the protein for complementation group I. Alternative splicing results in two transcript variants encoding different isoforms. [provided by RefSeq, Jul 2008]

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 0 ACMG points.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
POLGNM_002693.3 linkc.3650C>T p.Ala1217Val missense_variant Exon 23 of 23 ENST00000268124.11 NP_002684.1 P54098E5KNU5
FANCINM_001113378.2 linkc.*362G>A 3_prime_UTR_variant Exon 38 of 38 ENST00000310775.12 NP_001106849.1 Q9NVI1-3

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
POLGENST00000268124.11 linkc.3650C>T p.Ala1217Val missense_variant Exon 23 of 23 1 NM_002693.3 ENSP00000268124.5 P54098
FANCIENST00000310775.12 linkc.*362G>A 3_prime_UTR_variant Exon 38 of 38 1 NM_001113378.2 ENSP00000310842.8 Q9NVI1-3

Frequencies

GnomAD3 genomes
AF:
0.0000855
AC:
13
AN:
152132
Hom.:
0
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.0000724
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.00
Gnomad ASJ
AF:
0.00
Gnomad EAS
AF:
0.00154
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
GnomAD3 exomes
AF:
0.0000676
AC:
17
AN:
251306
Hom.:
0
AF XY:
0.0000663
AC XY:
9
AN XY:
135836
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.00
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.000761
Gnomad SAS exome
AF:
0.0000653
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.00000880
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.0000849
AC:
124
AN:
1460672
Hom.:
0
Cov.:
30
AF XY:
0.0000826
AC XY:
60
AN XY:
726784
show subpopulations
Gnomad4 AFR exome
AF:
0.0000598
Gnomad4 AMR exome
AF:
0.00
Gnomad4 ASJ exome
AF:
0.00
Gnomad4 EAS exome
AF:
0.00111
Gnomad4 SAS exome
AF:
0.000151
Gnomad4 FIN exome
AF:
0.00
Gnomad4 NFE exome
AF:
0.0000549
Gnomad4 OTH exome
AF:
0.0000663
GnomAD4 genome
AF:
0.0000855
AC:
13
AN:
152132
Hom.:
0
Cov.:
32
AF XY:
0.0000404
AC XY:
3
AN XY:
74338
show subpopulations
Gnomad4 AFR
AF:
0.0000724
Gnomad4 AMR
AF:
0.00
Gnomad4 ASJ
AF:
0.00
Gnomad4 EAS
AF:
0.00154
Gnomad4 SAS
AF:
0.00
Gnomad4 FIN
AF:
0.00
Gnomad4 NFE
AF:
0.0000294
Gnomad4 OTH
AF:
0.00
Alfa
AF:
0.0000966
Hom.:
0
Bravo
AF:
0.0000945
ExAC
AF:
0.0000494
AC:
6
Asia WGS
AF:
0.000577
AC:
2
AN:
3478

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:9
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

not provided Uncertain:2
Aug 09, 2019
GeneDx
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Collection Method: clinical testing

Reported previously in an individual with sensory ataxic neuropathy dysarthria and ophthalmoparesis (SANDO) who had a second POLG variant identified as well as a variant in the SLC25A4 gene and a mtDNA deletion in muscle (Tanaka et al., 2013).; In silico analysis, which includes protein predictors and evolutionary conservation, supports a deleterious effect; This variant is associated with the following publications: (PMID: 23524600, 27987238) -

Aug 01, 2021
CeGaT Center for Human Genetics Tuebingen
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

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

The NM_002693.2:c.3650C>T (NP_002684.1:p.Ala1217Val) [GRCH38: NC_000015.10:g.89316821G>A] variant in FANCI gene is interpretated to be a Uncertain Significance based on ACMG guidelines (PMID: 25741868). This variant meets the following evidence codes reported in the ACMG-guideline. PP3:Computational evidence/predictors indicate the variant has deleterious effect on FANCI structure, function, or protein-protein interaction. Based on the evidence criteria codes applied, the variant is suggested to be Uncertain Significance. -

Jul 23, 2024
Labcorp Genetics (formerly Invitae), Labcorp
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Collection Method: clinical testing

This sequence change replaces alanine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 1217 of the POLG protein (p.Ala1217Val). This variant is present in population databases (rs199751339, gnomAD 0.08%). This missense change has been observed in individual(s) with sensory ataxic neuropathy, dysarthria, and ophthalmoparesis (SANDO) (PMID: 23524600). ClinVar contains an entry for this variant (Variation ID: 206575). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt POLG protein function with a positive predictive value of 95%. Experimental studies are conflicting or provide insufficient evidence to determine the effect of this variant on POLG function (PMID: 27987238). 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. -

not specified Uncertain:1
Mar 28, 2017
Athena Diagnostics
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

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;C4551995:Mitochondrial DNA depletion syndrome 1 Uncertain:1
Nov 24, 2021
Fulgent Genetics, Fulgent Genetics
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

POLG-Related Spectrum Disorders Uncertain:1
Nov 15, 2017
Illumina Laboratory Services, Illumina
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Collection Method: clinical testing

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). Publications were found based on this search. However, the evidence from the literature, in combination with allele frequency data from public databases where available, was not sufficient to rule this variant in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance. -

Inborn genetic diseases Uncertain:1
Dec 04, 2024
Ambry Genetics
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Collection Method: clinical testing

The c.3650C>T (p.A1217V) alteration is located in exon 23 (coding exon 22) of the POLG gene. This alteration results from a C to T substitution at nucleotide position 3650, causing the alanine (A) at amino acid position 1217 to be replaced by a valine (V). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Fanconi anemia complementation group I Uncertain:1
Nov 17, 2017
Illumina Laboratory Services, Illumina
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Collection Method: clinical testing

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases did not allow this variant to be ruled in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Pathogenic
0.61
BayesDel_addAF
Uncertain
0.12
D
BayesDel_noAF
Pathogenic
0.31
CADD
Pathogenic
26
DANN
Pathogenic
1.0
DEOGEN2
Uncertain
0.78
D;D
Eigen
Pathogenic
0.91
Eigen_PC
Pathogenic
0.92
FATHMM_MKL
Pathogenic
0.99
D
LIST_S2
Pathogenic
0.99
.;D
M_CAP
Pathogenic
0.36
D
MetaRNN
Uncertain
0.71
D;D
MetaSVM
Pathogenic
1.0
D
MutationAssessor
Uncertain
2.4
M;M
PrimateAI
Uncertain
0.69
T
PROVEAN
Uncertain
-2.9
D;D
REVEL
Uncertain
0.63
Sift
Uncertain
0.011
D;D
Sift4G
Uncertain
0.013
D;D
Polyphen
1.0
D;D
Vest4
0.78
MVP
0.98
MPC
0.66
ClinPred
0.77
D
GERP RS
6.0
Varity_R
0.39
gMVP
0.68

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

LitVar

Below is the list of publications found by LitVar. It may be empty.

Other links and lift over

dbSNP: rs199751339; hg19: chr15-89860052; COSMIC: COSV51519503; COSMIC: COSV51519503; API