MNGIE is caused by mutations in the TYMP gene. These mutations result in the insufficient activity of an enzyme called thymidine phosphorylase (TP) in MNGIE patients.2
Parents can either have MNGIE or be carriers of the genetic mutation. Carriers are people who are healthy, but can still pass on their genetic mutation. Both female and male children can inherit MNGIE.
If 2 parents who are carriers of MNGIE have a child, there is a:
Parent with TYMP gene mutation
Parent with TYMP gene mutation
Child without MNGIE or TYMP gene mutation
Offspring will not develop MNGIE
Child without MNGIE but carries TYMP gene mutation
Can pass on TYMP gene mutation. Offspring might develop MNGIE
Child with MNGIE
Can pass on TYMP gene mutation. Offspring might develop MNGIE
Parent with TYMP gene mutation
Parent with TYMP gene mutation
Child without MNGIE or TYMP gene mutation
Offspring will not develop MNGIE
Child without MNGIE but carries TYMP gene mutation
Can pass on TYMP gene mutation. Offspring might develop MNGIE
Child with MNGIE
Can pass on TYMP gene mutation. Offspring might develop MNGIE
Symptoms can include abdominal pain or cramps, vomiting/nausea, diarrhea, abnormal bowel sounds, intestinal pseudo-obstruction, feeling full early, delayed stomach emptying, difficulty swallowing, etc.
Most patients experience thinness during the course of disease.
Symptoms can include drooping of the upper eyelids, weakness of muscles that move the eyes, damage to the peripheral nerves causing abnormal sensations and weakness in the feet and hands.
A blood sample is taken to measure the levels of two metabolites, thymidine and deoxyuridine. Elevated levels of plasma thymidine and deoxyuridine are sufficient to make the diagnosis of MNGIE.
A blood sample is taken to measure thymidine phosphorylase activity. Low thymidine phosphorylase activity can support a diagnosis of MNGIE.
In MNGIE patients, an MRI of the brain typically shows abnormal white matter, caused by a brain condition called leukoencephalopathy. This finding supports a diagnosis of MNGIE.
A blood, saliva or cheek swab sample is taken for genetic sequencing to see if there are any mutations in the TYMP gene. Mutations in the TYMP gene can confirm a diagnosis of MNGIE.
Below are some resources with information about MNGIE and mitochondrial diseases.