Approximately one year prior to transplant, the diagnosis of MNGIE was made based on GI dysfunction, neurologic involvement (neuropathic pain, bilateral foot drop, leukoencephalopathy on MRI), and cachexia with severe muscle weakness. Genetic testing identified a novel TYMP mutation (homozygous for c.214+1G>T, intron 2, in canonical splice site). Here, TYMP is linked to mitochondrial neurogastrointestinal encephalomyopathy.