Mitochondrial DNA Depletion due to Mutations in the TK2 Gene



Thymidine kinase 2 (TK2), encoded by the TK2 gene, is an essential component of the mitochondrial nucleotide salvage pathway responsible for the maintenance of mitochondrial deoxyribonucleotide pools. TK2 mutations lead to mitochondrial DNA (mtDNA) depletion syndrome. Although the myopathic type of mtDNA depletion syndrome seemed to be the main associated clinical phenotype, other clinical features such as central nervous system and liver involvement have been described, expanding the clinical spectrum of clinical spectrum of this condition. Cellular compensatory mechanisms leading to normal activities of the mitochondrial respiratory chain and even reversion of mtDNA depletion have been observed. Mouse models of this disease have revealed altered neuronal bioenergetics and neurodegeneration with high relevance for the mechanisms of neurological involvement in mtDNA depletion syndromes.


Mitochondrial DNA depletion TK2 gene Thymidine kinase 2 


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© Springer Science+Business Media, LLC 2013

Authors and Affiliations

  1. 1.BMC Medical GeneticsLondonUK
  2. 2.Department of Molecular and Human GeneticsBaylor College of Medicine and Texas Children’s Hospital, Clinical Care CenterHoustonUSA

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