Catalyzes the decarboxylation of L-3,4-dihydroxyphenylalanine (DOPA) to dopamine, L-5-hydroxytryptophan to serotonin and L-tryptophan to tryptamine.
Catecholamine biosynthesis; dopamine biosynthesis; dopamine from L-tyrosine: step 2/2.
Defects in DDC are the cause of aromatic L-amino-acid decarboxylase deficiency (AADCD) [MIM:608643]. AADCD deficiency is an inborn error in neurotransmitter metabolism that leads to combined serotonin and catecholamine deficiency. It causes developmental and psychomotor delay, poor feeding, lethargy, ptosis, intermittent hypothermia, gastrointestinal disturbances. The onset is early in infancy and inheritance is autosomal recessive.