SLEEP AND CIRCADIAN EFFECTS FROM LOSS OF SEROTONIN
Sleep and Rhythm Consequences of a Genetically Induced Loss of Serotonin
Smaranda Leu-Semenescu, MD1,7; Isabelle Arnulf, MD, PhD1,7; Caroline Decaix, PhD2; Fathi Moussa, PhD3; Fabienne Clot, PhD4; Camille Boniol, RN2; Yvan Touitou, PhD5; Richard Levy, MD, PhD2; Marie Vidailhet, MD6,7; Emmanuel Roze, MD, PhD6,8
1Sleep Disorders Unit, Pitié-Salpêtrière Hospital, AP-HP, Paris, France; 2Department of Neurology, Saint-Antoine Hospital, AP-HP, Paris 6 University, Paris, France; 3Department of Biochemistry, Trousseau Hospital, AP-HP, Paris 6 University, Paris, France; 4Department of Genetics and Cytogenetics, Pitié-Salpêtrière Hospital, AP-HP, Paris, France; 5U713, INSERM, Paris 6 University, Paris, France; 6Department of Neurology, Pitié-Salpêtrière Hospital, AP-HP, Paris 6 University, Paris, France; 7UMR 975, INSERM, Paris 6 University, Paris, France; 8UMRS 952, INSERM, Paris 6 University, Paris, France
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, attention/executive 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.
Keywords: Sepiapterin reductase deficiency, hypersomnia, melatonin, ultradian sleep-wake rhythm, tetrahydrobiopterin, serotonin