Facial dysmorphic signs of DS are central to the clinical recognition of the condition. Illustraged above are upslant of palpebral fissures, epicanthic folds, flat nasal bridge, small nasal tip, open mouth and protruding tongue conducive to drooling. Among the the most consistent combination of signs includes the trio: decreased muscle tone ("floppy baby", an open mouth - protruding or thrusting of the tongue and intellectual and motor developmental delay.  

With growth and aging, the DS facial features may become less striking (note that a growing number of patients undergo surgical removal of epicanthic folds). Less strining features as depicted by the icon to the right may prompt parents to reject the diagnosis and prognostic implications. (opening the icons leads to additional illustrations and notes)