rs779072487

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM2PP3

The NM_002693.3(POLG):​c.3671T>G​(p.Ile1224Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,674 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. I1224T) has been classified as Uncertain significance.

Frequency

Genomes: not found (cov: 32)
Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

POLG
NM_002693.3 missense

Scores

8
10
1

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 8.91

Publications

0 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]
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]
FANCI Gene-Disease associations (from GenCC):
  • Fanconi anemia complementation group I
    Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: ClinGen, Labcorp Genetics (formerly Invitae), G2P
  • Fanconi anemia
    Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

PM2
Very rare variant in population databases, with high coverage;
PP3
MetaRNN computational evidence supports a deleterious effect, 0.824

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
POLGNM_002693.3 linkc.3671T>G p.Ile1224Ser missense_variant Exon 23 of 23 ENST00000268124.11 NP_002684.1 P54098E5KNU5
FANCINM_001113378.2 linkc.*341A>C 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.3671T>G p.Ile1224Ser missense_variant Exon 23 of 23 1 NM_002693.3 ENSP00000268124.5 P54098
FANCIENST00000310775.12 linkc.*341A>C 3_prime_UTR_variant Exon 38 of 38 1 NM_001113378.2 ENSP00000310842.8 Q9NVI1-3

Frequencies

GnomAD3 genomes
Cov.:
32
GnomAD4 exome
AF:
0.00000137
AC:
2
AN:
1461674
Hom.:
0
Cov.:
30
AF XY:
0.00000275
AC XY:
2
AN XY:
727164
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33472
American (AMR)
AF:
0.00
AC:
0
AN:
44722
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26136
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39700
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86258
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53412
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5766
European-Non Finnish (NFE)
AF:
0.00000180
AC:
2
AN:
1111822
Other (OTH)
AF:
0.00
AC:
0
AN:
60386
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.550
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance
GnomAD4 genome
Cov.:
32

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:1
Revision: criteria provided, single submitter
LINK: link

Submissions by phenotype

Progressive sclerosing poliodystrophy Uncertain:1
Oct 05, 2022
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

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. 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. ClinVar contains an entry for this variant (Variation ID: 1374967). This variant has not been reported in the literature in individuals affected with POLG-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces isoleucine, which is neutral and non-polar, with serine, which is neutral and polar, at codon 1224 of the POLG protein (p.Ile1224Ser). -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Pathogenic
0.59
BayesDel_addAF
Pathogenic
0.40
D
BayesDel_noAF
Pathogenic
0.33
CADD
Uncertain
25
DANN
Uncertain
0.99
DEOGEN2
Pathogenic
0.83
D;D
Eigen
Uncertain
0.51
Eigen_PC
Uncertain
0.61
FATHMM_MKL
Pathogenic
0.99
D
LIST_S2
Uncertain
0.94
.;D
M_CAP
Uncertain
0.23
D
MetaRNN
Pathogenic
0.82
D;D
MetaSVM
Pathogenic
0.85
D
MutationAssessor
Uncertain
2.5
M;M
PhyloP100
8.9
PrimateAI
Uncertain
0.56
T
PROVEAN
Uncertain
-4.3
D;D
REVEL
Pathogenic
0.69
Sift
Uncertain
0.0010
D;D
Sift4G
Uncertain
0.0020
D;D
Polyphen
0.62
P;P
Vest4
0.86
MutPred
0.52
Gain of disorder (P = 0.0043);Gain of disorder (P = 0.0043);
MVP
0.98
MPC
0.62
ClinPred
0.99
D
GERP RS
6.0
PromoterAI
0.036
Neutral
Varity_R
0.68
gMVP
0.90

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: rs779072487; hg19: chr15-89860031; API