Aromatic L-amino acid decarboxylase deficiency: clinical features, drug therapy and follow-up.

Background: Aromatic L-amino acid decarboxylase (AADC) deficiency is a disorder of biogenic amine metabolism resulting in generalized combined deficiency of serotonin, dopamine and catecholamines. Main clinical features are developmental delay, muscular hypotonia, dystonia, oculogyric crises and additional extraneurological symptoms. Response to therapy has been variable and unsatisfactory; the overall prognosis is guarded.