In addition, obstructive sleep apnea syndrome (OSAS) had been observed in DS people with prevalence about 45-79% in the literature (de Miguel-Diez, Villa-Asensi et al. 2003; Dyken, Lin-Dyken et al. 2003; Shott, Amin et al. 2006; Fitzgerald, Paul et al. 2007), which is much higher than the 1-3% prevalence rate in general population (Holmes 1993; Gislason and Benediktsdottir 1995). The reasons of DS people prone to have OSAS are due to the combination of anatomical and physiological factors. In DS people, facial dysmorphism (midfacial hypoplasia, mandibular hypoplasia), macroglossia, small hypopharynx, pharyngeal hypotonia, tonsil and adenoid enlargement, obesity, laryngomalacia, and tracheomalacia contributed to upper airway obstructions in DS people (Trois, Capone et al. 2009; Pandit and Fitzgerald 2012). In addition, DS people has increased incidence of lower respiratory tract diseases including gastroesophageal reflux, immunological dysfunction, tracheal bronchus, airway malacia, congenital heart disease, and pulmonary hypoplasia, which will predispose to OSAS. While growing up, DS people still have generalized hypotonia with increasing risk of developing hypothyroidism and obesity, which are also risk factors for OSAS (Trois, Capone et al. 2009).