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
Consequence
NM_002693.3 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Uncertain_significance. Variant got 0 ACMG points.
Transcripts
RefSeq
Ensembl
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
---|---|---|---|---|---|---|---|---|---|---|
POLG | ENST00000268124.11 | c.3650C>T | p.Ala1217Val | missense_variant | Exon 23 of 23 | 1 | NM_002693.3 | ENSP00000268124.5 | ||
FANCI | ENST00000310775.12 | c.*362G>A | 3_prime_UTR_variant | Exon 38 of 38 | 1 | NM_001113378.2 | ENSP00000310842.8 |
Frequencies
GnomAD3 genomes AF: 0.0000855 AC: 13AN: 152132Hom.: 0 Cov.: 32
GnomAD3 exomes AF: 0.0000676 AC: 17AN: 251306Hom.: 0 AF XY: 0.0000663 AC XY: 9AN XY: 135836
GnomAD4 exome AF: 0.0000849 AC: 124AN: 1460672Hom.: 0 Cov.: 30 AF XY: 0.0000826 AC XY: 60AN XY: 726784
GnomAD4 genome AF: 0.0000855 AC: 13AN: 152132Hom.: 0 Cov.: 32 AF XY: 0.0000404 AC XY: 3AN XY: 74338
ClinVar
Submissions by phenotype
not provided Uncertain:2
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) -
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Progressive sclerosing poliodystrophy Uncertain:2
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. -
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
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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
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POLG-Related Spectrum Disorders Uncertain:1
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
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
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:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at