Ornithine transporter of the mitochondrial inner membrane; exports ornithine from mitochondria as part of arginine biosynthesis; functionally complemented by human ortholog, SLC25A15, which is associated with hyperornithinaemia-hyperammonaemia-homocitrullinuria (HHH) syndrome, but HHH-associated variants fail to complement. Here, SLC25A15 is linked to ornithine translocase deficiency.