Non-24-hour sleep-wake syndrome in a 38-year-old sighted male-to-female transsexual

Non-24-hour sleep-wake syndrome is characterized by complaints of insomnia and a lacking synchronization between the endogenous sleep-wake rhythm and the environmental light-dark cycle which leads to a daily delay of sleep onset and wake times of typically 1 hour. It is common in totally blind individuals but very rare in sighted individuals. We report the case of a sighted 38-year-old male-to-female transsexual. The patient complained about falling asleep 1 hour later every day and difficulties to fall asleep. She reported that there was no association between the onset of hormone replacement therapy 13 years ago or the sex transformation 9 years ago. Diagnosis was made by the patients medical history, sleep log for 3 weeks and subsequent actigraphy for 3 weeks. Cerebral imaging showed no pathology. Drug-free 32-hour polysomnography (PSG) revealed sleep-onset and -maintenance insomnia, prolonged sleep duration, and delayed sleep onset. The results of the long-term PSG were confirmed in another 3 PSGs that were adjusted to the patients delayed sleep onset and combined with measurements of melatonin, cortisol, and growth hormone (GH). As known for different circadian rhythms (dim light melatonin onset, core body temperature), daily delay of melatonin, cortisol and GH according to the sleep onset delay was observed. Successive treatments with 2–4 mg melatonin, 1000 mg vitamin B₁₂, and 12.5–25 mg agomelatine were not effective but caused mild to moderate side effects.