Clinical significance of cataplexy and HLADR1501 in narcolepsy

Clinical symptoms and multiple sleep latency test (MSLT) measures among narcoleptic patients with both cataplexy and HLADR1501 were compared with cataplexy-free narcoleptic patients with a positive finding of HLADR1501 and cataplexy-free patients without HLADR1501. Both mean sleep onset latencies and rapid eye movement (REM) latencies on MSLT were shorter in the patients with cataplexy compared with the cataplexy-free patients. In four cataplexy-free patients without HLADR1501, nocturnal sleep was remarkably long and their excessive daytime sleepiness did not respond to treatment. The findings suggest that the severity and disease mechanism of narcolepsy might become heterogenous when cataplexy and HLADR1501 are considered.