title: Disorder in the serotonergic system due to tryptophan hydroxylation impairment: a cause of hypothalamic syndrome?
abstract: BACKGROUND
  The hypothalamus regulates basic homeostasis such as appetite, circadian rhythm, autonomic and pituitary functions. Dysregulation in these functions results in the hypothalamic syndrome, a rare disorder of various origins. Since serotonin (5-HT) modulates most of the above-mentioned homeostasis, a defect in the serotonergic system can possibly participate in this syndrome.
  
  
  METHODS
  We describe a girl suffering from hypothalamic syndrome with a decreased concentration of 5-hydroxytryptophan (5-HTP) and a normal level of tryptophan in the cerebrospinal fluid (CSF) suggesting a functional defect in tryptophan hydroxylase (TPH). TPH is a rate-limiting enzyme in the synthesis of the neurotransmitter 5-HT.
  
  
  RESULTS
  Therapeutic intervention with 5-HTP, carbidopa and a specific serotonin reuptake inhibitor significantly improved her clinical symptoms and caused biochemical normalisation of neurotransmitters.
  
  
  CONCLUSIONS
  The girl described had the typical symptoms of a hypothalamic disorder and a defective serotonergic metabolism, a relationship which has not been reported before. Therapeutic interventions to restore 5-HT metabolism resulted in clinical improvement. We suggest that investigation of 5-HT metabolism in CSF of patients with this rare disorder is included in the aetiological work-up.
authors.affiliation: Department of Paediatrics, Maastricht University Medical Centre, Maastricht, The Netherlands. da.schott@mumc.nl
authors.forename: D A
authors.initials: DA
authors.lastname: Schott
authors.forename: J
authors.initials: J
authors.lastname: Nicolai
authors.forename: J E
authors.initials: JE
authors.lastname: de Vries
authors.forename: I M L W
authors.initials: IM
authors.lastname: Keularts
authors.forename: M E
authors.initials: ME
authors.lastname: Rubio-Gozalbo
authors.forename: W J M
authors.initials: WJ
authors.lastname: Gerver
mesh_terms: D002675:Child, Preschool; D004700:Endocrine System Diseases / Q000134:cerebrospinal fluid / Q000150:complications* / Q000209:etiology* / Q000378:metabolism; D005260:Female; D006801:Humans; D006900:Hydroxylation / Q000235:genetics / Q000502:physiology; D007027:Hypothalamic Diseases / Q000209:etiology* / Q000378:metabolism; D008954:Models, Biological; D009765:Obesity / Q000175:diagnosis / Q000209:etiology; D012701:Serotonin / Q000378:metabolism*; D013577:Syndrome; D014364:Tryptophan / Q000134:cerebrospinal fluid / Q000378:metabolism*; D014365:Tryptophan Hydroxylase / Q000378:metabolism*
chemical_list: D012701:Serotonin; D014364:Tryptophan; D014365:Tryptophan Hydroxylase