TK2-Related Mitochondrial DNA Depletion Syndrome (TK2-MDS)
What is TK2-related mitochondrial DNA depletion syndrome?
TK2-related mitochondrial DNA depletion syndrome (TK2-MDS) is a rare, genetic disorder that is characterized by progressive muscle weakness. It is typically fatal during childhood, as the muscles in charge of breathing become too weak, leading to respiratory failure.
What are the symptoms of TK2-related mitochondrial DNA depletion syndrome?
Affected individuals usually recognize symptoms during early childhood, such as progressive muscle weakness and the loss of motor skills. Children will regress and lose the milestones they have already reached, such as eating, walking, and talking. Other symptoms include droopy eyelids, enlarged liver, seizures, and hearing loss, although not all affected individuals experience these things.
What causes TK2-related mitochondrial DNA depletion syndrome?
A mutated TK2 gene is the cause of this condition, which is inherited in an autosomal recessive pattern. It is responsible for the thymidine kinase 2 enzyme, which is needed for the maintenance and production of mitochondrial DNA (mtDNA). When this gene is mutated, there is a lower amount of the enzyme, meaning that there is less repair and maintenance of mtDNA. Therefore, mitochondrial function is impacted, leading to the characteristic symptoms.
How is TK2-related mitochondrial DNA depletion syndrome diagnosed?
Medical professionals will look for the characteristic symptoms of TK2-MDS, followed by testing the mtDNA content in the skeletal muscles. Molecular genetic testing is used to confirm a diagnosis.
What are the treatments for TK2-related mitochondrial DNA depletion syndrome?
An interdisciplinary team is necessary for the best treatment of this condition. There is no cure, and treatment is symptomatic. Physical therapy, gastronomy tubes, physiotherapy, hearing aids, and antiseizure medication are all used in treatment.