Patients with TYMP mutations typically present with combined OXPHOS deficiency associated with mtDNA deletions/depletion rather than a primary complex III deficiency, and have mitochondrial neurogastrointestinal encephalomyopathy (MNGIE, MIM 603041) as opposed to the primary lactic acidosis and renal tubulopathy observed in our patient [23]. This evidence concerns the gene TYMP and hyperinsulinemic hypoglycemia, familial, 4.