Excessive daytime somnolence is one of the common complaints in patients with myotonic dystrophy. Here we report a 60-year-old female case of myotonic dystrophy type 1 with narcolepsy due to medical condition. The size of the CTG repeat in the 3' untranslated region of the DMPK gene was 1,800-2,400 repeats. Brain MRI was normal. Polysomnography revealed sleep apnea and chronic alveolar hypoventilation. Multiple sleep latency tests revealed normal sleep latencies and sleep onset REM was not observed. Orexin/hypocretin in the cerebrospinal fluid was markedly decreased to an undetectable level. Such sleep-related disorders may worsen the quality of life and possibly cause sudden death in patients with myotonic dystrophy. Narcolepsy associated with myotonic dystrophy should be evaluated appropriately.
ASJC Scopus subject areas
- Clinical Neurology