Inside the brain of patients with AADC deficiency the amount of dopamine and serotonin is very low. This is because the AADC enzyme is responsible for the production of both dopamine and serotonin. Surprisingly however, it was noticed in 1998 that some patients with AADC deficiency have normal or even high levels of dopamine in their urine. This suggested that at least some AADC patients do have the ability to produce large amounts of dopamine and understanding this could help find a new treatment to increase dopamine production in the brain. Because of this Dr Marcel Verbeek and Dr Michel Willemsen set out to discover how these patients had high amounts of dopamine in their urine.
Click on the link for more information... http://www.aadcresearch.org/page/urinary-dopamine-in-aadc-deficiency/