Mitochondrial neurogastrointestinal encephalopathy syndrome

Mitochondrial neurogastrointestinal encephalopathy syndrome
Other names	MNGIE syndrome; Mitochondrial DNA depletion syndrome 1 (MNGIE type); POLIP syndrome
Structure of thymidine phosphorylase enzyme, the main gene product of the TYMP gene. Mutations in the TYMP gene result in the loss of function of thymidine phosphorylase activity leading to the onset of MNGIE.[1]

Mitochondrial neurogastrointestinal encephalopathy syndrome (MNGIE) is a rare autosomal recessive mitochondrial disease.^[2] It has been previously referred to as polyneuropathy, ophthalmoplegia, leukoencephalopathy, and intestinal pseudoobstruction (POLIP syndrome).^[3] The disease presents in childhood, but often goes unnoticed for decades.^[2][4][5] Unlike typical mitochondrial diseases caused by mitochondrial DNA (mtDNA) mutations, MNGIE is caused by mutations in the TYMP gene, which encodes the enzyme thymidine phosphorylase.^[2][5] Mutations in this gene result in impaired mitochondrial function, leading to intestinal symptoms as well as neuro-ophthalmologic abnormalities.^[2][4] A secondary form of MNGIE, called MNGIE without leukoencephalopathy, can be caused by mutations in the POLG gene.^[3]