Down syndrome (DS), or trisomy 21, is a genetic disorder caused by the presence of an extra copy of chromosome 21, leading to various characteristic physical features as well as developmental and cognitive delays. Obstructive sleep apnea syndrome (OSAS) is a common disorder in both adult and pediatric patients with DS. Several characteristics of DS may contribute to the development or worsening of OSAS. Numerous murine models of DS exist. A number of studies have explored apneas and the risk of upper airway obstruction in these models, but up until now, only in adulthood.