Maple syrup urine disease is an autosomal recessive disorder characterised by reduced breakdown of branched-chain amino acids (leucine, isoleucine and valine). This results from a deficiency of the branched-chain alpha-keto acid dehydrogenase complex.

Consequences

• increased alpha-ketoacids in the blood
• sweet 'maple syrup' swelling urine
• if untreated: severeneurological defects, ketoacidosis, death
• treatment is restricting leucine, isoleucine and valine in the diet