SLC25A15 variants cause hyperornithinemia-hyperammonemia-homocitrullinemia syndrome

SLC25A15 encodes one of two ornithine-citrulline antitransporters that exchanges cytosolic ornithine for citrulline in the mitochondrial matrix; the second, SLC25A2 is partially functionally redundant. Both transporters play a role in moving substrates required for the urea cycle across the mitochondrial membrane, and consistent with this, mutations in SLC25A15 are associated with the urea cycle disorder hyperornithenemia-hyperammonia-homocitrullinuria (HHH) syndrome.

Summary from Reactome (R-HSA-9956508), read 2026-09-23.