Type 2 (childhood onset is rare): excessive daytime sleepiness, an irrepressible need to sleep or lapses into sleep (for at least three months), sometimes an improvement or disappearance of symptoms or a change in phenotype to idiopathic hypersomnia, normal hypocretin levels, specific paraclinical features, and rarely cataplexy [1,85]. The gene discussed is HCRT; the disease is idiopathic hypersomnia.