Sleep and Rhythm Consequences of a Genetically Induced Loss of Serotonin

Sleep. 2010 Mar;33(3):307-14. doi: 10.1093/sleep/33.3.307.

Abstract

Background: A genetic deficiency in sepiapterin reductase leads to a combined deficit of serotonin and dopamine. The motor phenotype is characterized by a dopa-responsive fluctuating generalized dystonia-parkinsonism. The non-motor symptoms are poorly recognized. In particular, the effects of brain serotonin deficiency on sleep have not been thoroughly studied.

Objective: We examine the sleep, sleep-wake rhythms, CSF neurotransmitters, and melatonin profile in a patient with sepiapterin reductase deficiency.

Patient: The patient was a 28-year-old man with fluctuating generalized dystonia-parkinsonism caused by sepiapterin reductase deficiency.

Methods: A sleep interview, wrist actigraphy, sleep log over 14 days, 48-h continuous sleep and core temperature monitoring, and measurement of CSF neurotransmitters and circadian serum melatonin and cortisol levels before and after treatment with 5-hydroxytryptophan (the precursor of serotonin) and levodopa were performed.

Results: Before treatment, the patient had mild hypersomnia with long sleep time (704 min), ultradian sleep-wake rhythm (sleep occurred every 11.8 +/- 5.3 h), organic hyperphagia, attentionlexecutive dysfunction, and no depression. The serotonin metabolism in the CSF was reduced, and the serum melatonin profile was flat, while cortisol and core temperature profiles were normal. Supplementation with 5-hydroxytryptophan, but not with levodopa, normalized serotonin metabolism in the CSF, reduced sleep time to 540 min, normalized the eating disorder and the melatonin profile, restored a circadian sleep-wake rhythm (sleep occurred every 24 +/- 1.7 h, P < 0.0001), and improved cognition.

Conclusion: In this unique genetic paradigm, the melatonin deficiency (caused by a lack of its substrate, serotonin) may cause the ultradian sleep-wake rhythm.

Publication types

  • Case Reports

MeSH terms

  • 5-Hydroxytryptophan / therapeutic use
  • Adult
  • Alcohol Oxidoreductases / deficiency*
  • Alcohol Oxidoreductases / genetics*
  • Antidepressive Agents, Second-Generation / therapeutic use
  • Consanguinity
  • Disorders of Excessive Somnolence / drug therapy
  • Disorders of Excessive Somnolence / enzymology
  • Disorders of Excessive Somnolence / genetics*
  • Dopamine / deficiency
  • Dopamine Agents / therapeutic use
  • Drug Therapy, Combination
  • Humans
  • Hydrocortisone / blood
  • Hyperphagia / drug therapy
  • Hyperphagia / enzymology
  • Hyperphagia / genetics
  • Levodopa / therapeutic use
  • Male
  • Melatonin / deficiency
  • Polysomnography
  • Serotonin / deficiency*
  • Sleep / drug effects
  • Sleep / genetics*
  • Sleep Disorders, Circadian Rhythm / drug therapy
  • Sleep Disorders, Circadian Rhythm / enzymology
  • Sleep Disorders, Circadian Rhythm / genetics*

Substances

  • Antidepressive Agents, Second-Generation
  • Dopamine Agents
  • Serotonin
  • Levodopa
  • 5-Hydroxytryptophan
  • Alcohol Oxidoreductases
  • sepiapterin reductase
  • Melatonin
  • Dopamine
  • Hydrocortisone