Pierre-Robin Sequence is not a syndrome, it’s a sequence. While it is a collection of features, one happens because of the one that came before.
The features are:
- Retrognathia/micrognathia (posterior mandible or very small mandible)
- Glossoptosis (downwards/posterior displacement of the tongue due to the small mandible
- Airway obstruction (because the tongue is in the way)
Pierre-Robin Sequence is associated with cleft palate (50% of children with the sequence have cleft palate). There are two proposed theories:
- The first is that the tongue simply gets in the way of the palate from fusing
- The second is that the tongue prevents the newly fused palate from staying fused (this is currently the more popular theory)
PRS, though not a syndrome itself, is associated with multiple syndromes including Stickler Syndrome, velocardiofacial syndrome, fetal alcohol syndrome and Treacher Collins Syndrome.