Pierre Robin Syndrome: Clinical Features
Pierre Robin Syndrome (PRS) is characterized by a classic triad: micrognathia (underdeveloped mandible), glossoptosis (posterior displacement of the tongue), and upper airway obstruction, with cleft palate present in many but not all cases 1, 2.
Core Craniofacial Features
The defining anatomical abnormalities include:
- Micrognathia: Severely underdeveloped lower jaw, which is the primary structural defect
- Glossoptosis: Backward displacement of the tongue into the pharynx, occurring secondary to the small mandible
- Cleft palate: Present with "variable inclusion" - not universally present but common 2
- The palate when affected is typically U-shaped and large 1
Airway and Respiratory Manifestations
Upper airway obstruction is the most critical clinical feature affecting morbidity and mortality:
- Respiratory distress present from birth 3
- Airway compromise ranges from mild positional obstruction to severe life-threatening obstruction requiring immediate intervention 2
- Subglottic obstruction may coexist 2
- Central sleep apnea can occur as a comorbidity 2
The airway obstruction results from the combination of mandibular hypoplasia causing posterior tongue displacement, which mechanically obstructs the pharyngeal airway.
Feeding Difficulties
Feeding problems are nearly universal and directly impact growth:
- Difficulty with oral feeding due to anatomical constraints 2, 4
- Poor weight gain and failure to thrive if not properly managed 5
- The combination of airway obstruction and cleft palate creates significant feeding challenges
Associated Otologic Features
Hearing loss occurs in PRS and can be both conductive and sensorineural 6:
- Bilateral serous otitis media (middle ear effusions) is common 6
- Conductive hearing loss predominates but sensorineural loss also occurs 6
- Proper audiologic evaluation is essential in all cases
Prenatal and Birth Presentation
When detected prenatally or at birth, look for:
- Mandibular hypoplasia visible on examination
- Immediate respiratory distress requiring positioning or intervention 3
- Reduced muscle tone may be present in some cases 3
Important Clinical Caveats
PRS can occur as an isolated sequence or as part of syndromic disease with a high rate of associated syndromes 2. This necessitates:
- Evaluation for other congenital anomalies
- Genetic assessment when syndromic features are present
- Rare associations like cervical diastematomyelia have been reported 3
The distinction between "sequence" terminology reflects that these features result from a cascade of developmental events initiated by mandibular hypoplasia, rather than independent malformations 7, 2.