Maple syrup urine disease (MSUD) (leucine encephalopathy) [7] is a genetic disorder caused by a genetic deficiency in the branched-chain alpha-keto acid dehydrogenase (BCKDH), which catalyzes the decarboxylation of alpha-keto acids derived from the metabolism of branched-chain amino acids (BCAA). Here, PPM1K is linked to maple syrup urine disease.