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. Conclusion: 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.
- Tryptophan hydroxylase
- TPH2 protein
- ONSET CENTRAL HYPOVENTILATION
- ALVEOLAR HYPOVENTILATION
- PRECOCIOUS PUBERTY
Schott, D. A., Nicolai, J., de Vries, J. E., Keularts, I. M., Rubio-Gozalbo, M. E., & Gerver, W. J. M. (2010). Disorder in the Serotonergic System due to Tryptophan Hydroxylation Impairment: A Cause of Hypothalamic Syndrome? Hormone Research in Paediatrics, 73(1), 68-73. https://doi.org/10.1159/000271918