title: Aromatic L-amino acid decarboxylase deficiency: diagnostic methodology.
abstract: Aromatic L-amino acid decarboxylase (EC. 4.1.1.28) deficiency is a newly described inborn error of metabolism that affects serotonin and dopamine biosynthesis. The major biochemical markers for this disease are increases of L-dopa, 3-methoxytyrosine, and 5-hydroxytryptophan in urine, plasma, and cerebrospinal fluid together with decreased cerebrospinal fluid concentrations of homovanillic acid and 5-hydroxyindoleacetic acid. In addition, concentrations of vanillactic acid are increased in the urine. Specific HPLC and gas chromatography-mass spectrometry methods are described that permit the identification and measurement of these metabolites in the above body fluids. Simplified assays for human plasma L-dopa decarboxylase and liver L-dopa and 5-hydroxytryptophan decarboxylase, used to demonstrate the enzyme deficiency, are also reported.
mesh_terms: D006916:5-Hydroxytryptophan / Q000097:blood / Q000134:cerebrospinal fluid / Q000652:urine; D001142:Aromatic-L-Amino-Acid Decarboxylases / Q000172:deficiency* / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D002851:Chromatography, High Pressure Liquid; D004296:Dopa Decarboxylase / Q000097:blood / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry; D006719:Homovanillic Acid / Q000031:analogs & derivatives / Q000134:cerebrospinal fluid / Q000652:urine; D006801:Humans; D006897:Hydroxyindoleacetic Acid / Q000134:cerebrospinal fluid; D007223:Infant; D007980:Levodopa / Q000097:blood / Q000134:cerebrospinal fluid / Q000652:urine; D008099:Liver / Q000201:enzymology; D008661:Metabolism, Inborn Errors / Q000175:diagnosis*; D012016:Reference Values; D014443:Tyrosine / Q000031:analogs & derivatives / Q000097:blood / Q000134:cerebrospinal fluid / Q000652:urine
chemical_list: C003753:vanillactic acid; D014443:Tyrosine; D007980:Levodopa; D006897:Hydroxyindoleacetic Acid; D006916:5-Hydroxytryptophan; D004296:Dopa Decarboxylase; D001142:Aromatic-L-Amino-Acid Decarboxylases; C008404:3-methoxytyrosine; D006719:Homovanillic Acid