Pierre-Robin Syndrome (PRS), also known as Pierre Robin sequence, is a congenital condition that affects the lower jaw and palate. The three main features that characterize PRS are:
- cleft palate (opening in the roof of the mouth)
- severe underdevelopment of the lower jaw (retrognathia)
- glossoptosis (airway obstruction caused by backwards displacement of the tongue base)
This condition occurs in approximately 1 in 8,500 to 14,000 births, and it’s equally common in males and females. There is a higher incidence in twins, which may be due to crowding in the uterus, restricting growth of the mandible (lower jaw). PRS may occur in isolation, but it is can be part of an underlying disorder or syndrome. The most common is Stickler Syndrome.
The condition is called a sequence because it is believed the underdeveloped mandible begins a sequence of events, which leads to the abnormal displacement of the tongue and subsequent formation of a cleft palate.
Patients can be seen by Texas Children's experts in Plastic Surgery.
Causes & Risk Factors
An exact cause of PRS is not known. It is believed that any external factor crowds the fetus and interferes with the growth of the lower jaw. Certain neurological conditions, which lead to decreased jaw movement in utero, can also restrict jaw growth. In addition, some studies demonstrate there may be genetic anomalies at chromosomes 2, 11 or 17.
Normally, between 9 to 11 weeks of gestation, the tongue moves down and away from the roof of the mouth. This allows space for the sides of the palate to shift to the midline and close. However, in PRS the small mandible keeps the tongue positioned higher in the mouth than normal, thereby interfering with the normal closure of the palate. This typically results in a wide U-shaped cleft of the soft and part of the hard palate.
Symptoms & Types
PRS is commonly characterized by:
- An unusual small lower jaw (micrognathia)
- Posterior displacement or retraction of the tongue (glossoptosis), which may cause upper airway obstruction
Incomplete closure of the roof of the mouth (cleft palate) is present in the majority of patients, and is commonly U-shaped tongue that is large compared to the jaw
Diagnosis & Tests
There’s no specific diagnostic test for PRS. Consulting with a genetic specialist can rule out other problems linked to this syndrome.
A diagnosis is made by precise physical examination of the infant, generally right after birth. A CT scan and sleep study may be required.
Treatment & Care
A multidisciplinary team approach is highly recommended for proper management of PRS. The goal of treatment is to focus on breathing and feeding, and optimizing growth and nutrition despite the predisposition for breathing difficulties. If there is evidence of airway obstruction (snorting breathing, apnea, difficulty taking a breath, or drops in oxygen), then the infant should be placed in the side or prone position, which helps bring the tongue base forward in many children.
In moderate cases, the patient will need to have a tube placed through the nose and into the airways to avoid airway blockage. In severe cases, surgery is needed to prevent a blockage in the upper airway. This is often done by distraction osteogenesis of the lower jaw, which stretches the tissue and grows new bone to make a larger jaw. In rare cases, patients need surgery to make a hole in the windpipe (tracheostomy) because the breathing problems are so severe.
Surgery will be needed to repair the cleft palate and this is done between 9 and 12 months of age, depending on the overall health of the child.
Living & Managing
Children affected with PRS usually reach full development and size. Infants with this condition should NOT be put on their back, to prevent the tongue from falling back into the airway.
Most children have normal speech after palate repair, but some will require speech therapy or a second operation later on to improve speech.
Feeding must be done very carefully to avoid choking and aspirating liquid into the airway.
Some complications that may occur are:
- Breathing difficulties, especially when the child sleeps
- Choking episodes
- Feeding difficulties
- Low blood oxygen and brain damage (due to difficulty breathing)