rs281865487
Variant summary
Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PS1_ModeratePM1PM2PP3_ModeratePP5
The NM_004614.5(TK2):c.191C>T(p.Thr64Met) variant causes a missense change. The variant allele was found at a frequency of 0.00000205 in 1,461,868 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 Conflicting classifications of pathogenicity (no stars). Another nucleotide change resulting in same amino acid change has been previously reported as Likely pathogenicin UniProt. Synonymous variant affecting the same amino acid position (i.e. T64T) has been classified as Likely benign.
Frequency
Consequence
NM_004614.5 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Likely_pathogenic. Variant got 9 ACMG points.
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | MANE | UniProt |
---|---|---|---|---|---|---|---|
TK2 | NM_004614.5 | c.191C>T | p.Thr64Met | missense_variant | 3/10 | ENST00000544898.6 |
Ensembl
Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | TSL | MANE | Appris | UniProt |
---|---|---|---|---|---|---|---|---|---|
TK2 | ENST00000544898.6 | c.191C>T | p.Thr64Met | missense_variant | 3/10 | 1 | NM_004614.5 | P1 |
Frequencies
GnomAD3 genomes ? Cov.: 32
GnomAD3 exomes AF: 0.00000795 AC: 2AN: 251476Hom.: 0 AF XY: 0.00 AC XY: 0AN XY: 135910
GnomAD4 exome AF: 0.00000205 AC: 3AN: 1461868Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1AN XY: 727228
GnomAD4 genome ? Cov.: 32
ClinVar
Submissions by phenotype
not provided Pathogenic:2
Likely pathogenic, criteria provided, single submitter | clinical testing | GeneDx | Aug 30, 2023 | Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 15907288, 33486010, 29602790) - |
Pathogenic, criteria provided, single submitter | clinical testing | Invitae | Oct 08, 2023 | This sequence change replaces threonine, which is neutral and polar, with methionine, which is neutral and non-polar, at codon 64 of the TK2 protein (p.Thr64Met). This variant is present in population databases (rs281865487, gnomAD 0.003%). This missense change has been observed in individual(s) with mitochondrial DNA depletion syndrome (PMID: 15907288, 33486010). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 38979). 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 TK2 protein function. For these reasons, this variant has been classified as Pathogenic. - |
Mitochondrial DNA depletion syndrome, myopathic form Uncertain:1
Uncertain significance, criteria provided, single submitter | clinical testing | Illumina Laboratory Services, Illumina | May 05, 2017 | The TK2 c.191C>T (p.Thr64Met) variant has been reported in at least two studies and is found in two affected siblings with the variant in a compound heterozygous state with a second missense variant (Tulinius et al. 2005; Chanprasert et al. 2013). The siblings were diagnosed with a myopathic form of mitochondrial DNA depletion syndrome, and presented with hypotonia, muscle weakness, and less than 10% mtDNA content in skeletal muscle. The p.Thr64Met variant was absent from 100 control alleles (Tulinius et al. 2005). This variant is reported at a frequency of 0.00003 in the Latino population of the Genome Aggregation Database, but this is based on one allele so the variant is presumed to be rare. The evidence for the p.Thr64Met variant is limited and it is therefore classified as a variant of unknown significance but suspicious for pathogenicity for mitochondrial DNA depletion syndrome. This variant was observed by ICSL as part of a predisposition screen in an ostensibly healthy population. - |
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at