0656 SYMPTOMATIC NARCOLEPSY AMONG INHERITED DISORDER,SUCH AS NIEMANN-PICK TYPE C

Abstract

The symptoms of narcolepsy can occur during the course of other neurological conditions. Inherited disorders, tumors and demyelinating diseases were the three most frequent causes for symptomatic narcolepsy. Among inherited disorders, Niemann-Pick type C (NPC), Myotonic dystrophy type 1 and Prader-Willi syndrome were major three disorders. NPC is an autosomal recessive and congenital neurological disorder characterized by the accumulation of cholesterol and glycosphingolipids in the peripheral tissues and in the brain. NPC had no effective treatment before, but since 2012, we can use Miglustat in Japan. Miglustat inhibits glucosylceramide synthase, an essential enzyme for the synthesis of most glycosphingolipids. In this study, 5 out of 10 cases have been treated with Miglustat. The 10 patients with NPC were included in the study. Patients or families were given informed consent for the lumbar puncture. We checked clinical symptoms, brain MRI, HLA and measured orexin levels. In this study, previous 5 cases were untreated by Miglustat, and recent 5 cases were treated by Miglustat. Six out of 10 cases had cataplexy. Four cases with normal orexin level (>200pg/ml) did not show cataplexy. The cases which orexin levels were low level (<110pg/ml) of intermediate levels (110-200pg/ml) exhibit cataplexy. In two cases with cataplexy, orexin levels at the onset were intermediate, and became lower in the later period. About recent one case, she had cataplexy with intermediate orexin level. Her cataplexy was reduced and orexin level was increased to normal level, and other symptom (dysphagia, and oculography) got better. The NPC patients with cataplexy have low or intermediate orexin levels. In the cases without cataplexy, their orexin levels were normal. Cataplexy and orexin measurement make a chance to early diagnose and treatment for NPC. a