Pierre Robin Sequence (PRS) is a rare condition present at birth, characterized by a specific set of physical abnormalities affecting the jaw and mouth. It is referred to as a “sequence” because one initial developmental issue leads to a cascade of other related problems. This condition can make it challenging for newborns to breathe and feed effectively, requiring careful medical attention from birth. PRS affects approximately 1 in 8,500 to 14,000 individuals. Understanding its features and management is important for affected families.
Understanding Pierre Robin Sequence
Pierre Robin Sequence is defined by a triad of features: an unusually small lower jaw (micrognathia), the tongue falling backward towards the throat (glossoptosis), and often, an opening in the roof of the mouth (cleft palate). Micrognathia, an underdeveloped and set-back lower jaw, is the initiating factor in this sequence. Due to the small jaw, the tongue does not have enough space and is displaced backward, which is known as glossoptosis. This backward displacement of the tongue can then obstruct the upper airway, leading to breathing difficulties.
The displaced tongue can also prevent the two sides of the palate from joining together during fetal development, resulting in a U-shaped cleft palate. These combined features can cause significant challenges with both breathing and feeding in infants. Airway obstruction can manifest as noisy breathing, snoring, or signs of obstructive sleep apnea, while feeding issues may include difficulty latching, prolonged feeding times, coughing, or choking. Addressing these concerns is a primary focus of care for newborns with PRS.
Origins and Related Conditions
Pierre Robin Sequence originates from a developmental cascade during fetal growth. The initial event involves the underdevelopment of the lower jaw, occurring around the seventh to eleventh week of pregnancy. This abnormal jaw development then sets off the sequence of other physical changes, including tongue displacement and cleft palate formation. While the exact cause is not always known, genetic factors play a role in many cases.
PRS can occur in isolation or as part of a broader genetic condition. When PRS occurs in isolation, changes in the DNA near the SOX9 gene are the most common genetic association, influencing the development of the jaw. In about a third of cases, PRS is linked to other genetic syndromes, such as Stickler syndrome or 22q11.2 deletion syndrome (also known as velocardiofacial syndrome). The presence of an associated syndrome can influence the overall health profile and management of the child.
Identification and Care
Pierre Robin Sequence can be suspected during pregnancy through prenatal ultrasounds. However, diagnosis is often made shortly after birth based on a physical examination of the newborn’s facial features. A healthcare team will observe the characteristic small jaw, backward tongue position, and often, the presence of a cleft palate. Further tests like a sleep study or a CT scan may be conducted to assess the severity of airway obstruction.
Care for infants with PRS primarily focuses on managing airway obstruction and ensuring adequate feeding. For mild cases, placing the baby on their stomach (prone position) can help gravity pull the tongue forward and keep the airway open. More severe breathing difficulties may require interventions such as a nasopharyngeal airway, which is a soft tube inserted through the nose to maintain an open airway. Surgical procedures like tongue-lip adhesion, where the tongue is temporarily attached to the lower lip, or mandibular distraction osteogenesis, which gradually lengthens the jaw, may be considered to improve breathing.
Feeding difficulties are also common, and a feeding therapist can provide guidance on specialized nipples or feeding positions. If oral feeding remains insufficient, a nasogastric (NG) tube can be used to deliver milk directly to the stomach. If a cleft palate is present, surgical repair is performed later, between 9 and 18 months of age. A multidisciplinary team, including neonatologists, plastic surgeons, and speech pathologists, often collaborates to provide comprehensive care.
Life Beyond Infancy
As children with Pierre Robin Sequence grow, many initial challenges, especially breathing and feeding, often improve. The lower jaw experiences significant growth during the first year of life, which helps create more space for the tongue and can resolve airway obstruction. This natural growth can lead to a reduction in the severity of breathing problems, with many children no longer needing special airway support as they get older.
Despite improvements in early childhood, some individuals may have ongoing needs. Children who had a cleft palate will often require speech therapy to address speech development issues. Orthodontic care may also be necessary due to the initial jaw abnormalities. Ongoing monitoring by a craniofacial team is recommended throughout childhood to address any emerging concerns, especially if the PRS was part of a larger genetic syndrome. With appropriate medical and surgical management, most children with PRS can lead healthy lives, with recent studies reporting overall survival rates as high as 95% by 10 years of age.