Interestingly, Hcrt levels are also reduced in other diseases associated with deficits in wakefulness including Guillain-Barre syndrome (Ripley et al., 2001; Kanbayashi et al., 2002) and myotonic dystrophy (Martínez-Rodríguez et al., 2003), while Hcrt levels are elevated in some patients with restless leg syndrome (Allen et al., 2002). This evidence concerns the gene HCRT and myotonic dystrophy.