Biochemical and clinical effects of tyrosine and tryptophan in the Rett syndrome.
In the Rett syndrome (RS), a progressive encephalopathy affecting girls, deficient neurotransmitter synthesis has been suggested as a pathogenetic mechanism. Nine girls with RS were treated with 0.3 g of tyrosine and 0.1 g of tryptophan per kg body weight for 2 to 17 weeks. This resulted in a median rise in the spinal fluid concentration of the dopamine metabolite homovanillic acid by 31%, and of the serotonin metabolite 5-hydroxyindoleacetic acid by 40%. This finding supports the hypothesis of a compromised neurotransmitter synthesis and indicates that it can be stimulated by supply of amino acid precursors. A double-blind cross-over trial including 11 girls did not show clinical improvement during a treatment period of 8 to 10 weeks.
Department of Neuropediatrics, John F Kennedy Institute, Glostrup, Denmark.
J B
JB
Nielsen
H C
HC
Lou
J
J
Andresen
D000293:Adolescent; D002648:Child; D004298:Dopamine / Q000378:metabolism; D004311:Double-Blind Method; D005260:Female; D006719:Homovanillic Acid / Q000134:cerebrospinal fluid*; D006801:Humans; D006897:Hydroxyindoleacetic Acid / Q000134:cerebrospinal fluid*; D015518:Rett Syndrome / Q000188:drug therapy* / Q000378:metabolism; D014364:Tryptophan / Q000627:therapeutic use*; D014443:Tyrosine / Q000627:therapeutic use*
D014443:Tyrosine; D006897:Hydroxyindoleacetic Acid; D014364:Tryptophan; D004298:Dopamine; D006719:Homovanillic Acid