TK2
Chr 16ARthymidine kinase 2
This gene encodes a mitochondrial deoxyribonucleoside kinase that phosphorylates thymidine, deoxycytidine, and deoxyuridine, which is essential for mitochondrial DNA synthesis. Mutations cause mitochondrial DNA depletion syndrome type 2 (myopathic type) and progressive external ophthalmoplegia with mitochondrial DNA deletions, both inherited in an autosomal recessive pattern. The pathogenic mechanism involves dominant-negative effects that disrupt mitochondrial DNA replication and maintenance.
Definitive — sufficient evidence for diagnostic panels
Population Genetics & Constraint
gnomAD v4 — loss-of-function & missense intolerance
Highly tolerant — LoF variants common in population
Mild missense constraint
Predictions shown for reference only — model trained on dominant genes, not applicable to AR conditions.
The Badonyi & Marsh prediction model was trained exclusively on dominant disease genes. Predictions are not reliable for genes with autosomal recessive inheritance and are shown at reduced opacity for reference only.
Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312.
ClinVar Variant Classifications
0 submitted variants in ClinVar
Protein Context — Lollipop Plot
TK2 · protein map & ClinVar variants
Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.
3D Protein StructureAlphaFold
External Resources
Links to major genomics databases and tools
Clinical Trials
Active and recruiting trials from ClinicalTrials.gov
External Resources
Links to major genomics databases and tools