Recent CSF and postmortem brain hypocretin measurements in human narcolepsy suggest that hypocretin deficiency is involved in the pathophysiology of the disease. Thus, it is important to study whether neurological disorders also have abnormal CSF hypocretin levels. We therefore measured hypocretins in the CSF of various neurological disorders and obstructive sleep apnea syndrome (OSAS) to identify altered hypocretin levels. CSF hypocretin levels in patients with OSAS and neurological diseases were almost within the normal range in Japanese populations. While, hypocretin levels in patients with narcolepsy-cataplexy are very low. The measurement of hypocretin levels is a useful diagnostic tool in Japanese patients with narcolepsycataplexy
