In MNGIE, a loss of TP activity leads to the accumulation of deoxyuridine (dUrd) and thymidine (Thd), which infiltrate through the mitochondrial pyrimidine remedy pathway, leading to an imbalance of deoxyuridine triphosphate pool (dNTP). The gene discussed is TYMP; the disease is mitochondrial neurogastrointestinal encephalomyopathy.