0814 Three Sleepy Siblings

Abstract Introduction Narcolepsy type 1 is caused by destruction of hypocretin-producing neurons, likely via a T-cell mediated autoimmune process, and clinically identified either CSF hypocretin deficiency or the presence cataplexy. Individuals with narcolepsy have an underlying genetic predisposition attributed to HLA DQB1*0602 gene. This variant has been linked increased propensity for sleepiness even in healthy adults. Relatives patients appear be at risk other disorders hypersomnolence such as idiopathic hypersomnia. Here we describe three siblings, all positive DQB1*0602, who presented distinct clinical features diagnostic 1, 2, Report Cases: A 15-year-old female was diagnosed based on typical cataplexy, excessive daytime sleepiness, mean sleep latency 2 min SOREMPs MSLT. Lumbar puncture (LP) performed 5 years after symptom onset showed low (9.3 pg/mL). Her older brother age 21 somewhat atypical hypnagogic hallucinations, paralysis. MSLT 6 SOREMPs. Despite LP normal (296.5 pg/mL) he 2. Their younger sister 19 progressive sleepiness. PSG/MSLT mild OSA (RDI 9.2) 6.5 without She does not The current findings are most consistent hypersomnia, although evaluate important next step. Similarly, repeat might demonstrate change over time. Conclusion These cases may support familial link between discordant cataplexy statuses these siblings implies mechanism beyond deficiency, possibly DQB1*0602. Identifying mechanisms aggregation central shed light pathophysiology disorders. Support (If Any)