ABSTRACT
As discussed in other chapters, narcolepsy is a common neurological disorders affecting 0.02% to 0.16% of the population (with cataplexy present). Although narcolepsy only occasionally occurs in multiplex families and monozygotic twin pairs are most commonly discordant, familial risk is increased. One to two percent of first-degree relatives are affected with narcolepsy-cataplexy, a 10 to 40-fold increase compared to general population prevalence (1).
