![]() The associated cleft prevents the formation of negative intraoral pressure, which is required to suck milk from the breast or bottle the micrognathia and glossoptosis further impede mechanical sucking. Gastroesophageal reflux and aspiration are common sequelae of this process. 7įeeding difficulties are common as infants struggle to breathe during eating. ![]() Depending on the severity of airway obstruction, some infants may maintain their airway when awake but suffer from obstruction when asleep, especially in the supine position. 7 To combat the obstructive forces, a high volume of energy is expended to continue breathing and is manifest by suprasternal retractions and the use of accessory muscles of respiration. 1, 2 Infants with PRS may have an obstruction of the airway at the level of the tongue base, which can result in repeated oxygen desaturations, apnea, and cyanosis. Moreover, although the tongue is typically noted to be of normal size, the hypoplastic mandible provides less volume in the oral cavity and forces the tongue to fit into a smaller space, which further serves to exacerbate the blockage of the posterior pharynx.Īirway obstruction, the completion of the triad, is a result of the abnormal positioning of the tongue, which serves to occlude the nasal and oral pharynx on inspiration. As a smaller mandible has less anterior projection, the tongue will in turn be shifted posteriorly. The position of the tongue is largely determined by the size and orientation of the mandible. Glossoptosis, defined as an abnormal posterior placement of the tongue, is the second characteristic feature of PRS. Microretrognathia in an infant with Pierre Robin sequence, best seen on lateral view. Jakobsen et al suggests that nonsyndromic PRS is associated with SOX9 and KCNJ2 dysregulation, both on chromosome 17, based on a series of unrelated PRS patients, one of whom had a balanced translocation between chromosomes 2 and 17. 4 Stickler syndrome is associated with mutations in COL2A1, COL9A1, COL11A1, and COL11A2, whereas velocardiofacial syndrome arises from a microdeletion of chromosome 22q11.2. This study concluded that 40% of PRS was isolated and 60% were associated with another syndrome, most commonly Stickler and velocardiofacial syndromes. 5 A new study by Izumi et al evaluated two cohorts of patients clinically diagnosed with PRS using fluorescence in situ hybridization (FISH) and array comparative genomic hybridization (CGH). Micrognathia is associated with deletions in 4p, 4q, 6q, and 11q, and duplications on 10q and 18q. 5 Cleft palate is associated with deletions on 2q and 4p, and duplications on 3p, 3q, 7q, 78q, 10 p, 14q, 16p, and 22q. Moreover, family members of PRS infants have a higher incidence of cleft lip and palate. Support for a genetic basis is evidenced by a high incidence of twins with PRS. 4 This phenotype is due to several causes and can be seen in isolation or in conjunction with a syndromic presentation. Pierre Robin sequence occurs in 1/8500 to 1/14,000 births. The two most common procedures for treatment, tongue–lip adhesion and distraction osteogenesis of the mandible, are discussed. Prior to considering any surgical procedure, the clinician should first rule out any sources of obstruction below the base of the tongue that would necessitate a tracheostomy. A proportion of PRS infants do not respond to conservative measures and will require further intervention. Early feeding via a nasogastric tube may also reduce the amount of energy needed and allow for early weight gain. If the infant continues to show evidence of desaturation, then placement of a nasopharyngeal tube is indicated. In the correct position, most children will also be able to feed normally. Positioning will resolve the airway obstruction in ~70% of cases. Infants with PRS should be evaluated by a multidisciplinary team to assess the anatomic findings, delineate the source of airway obstruction, and address airway and feeding issues. However, it is related to several other craniofacial anomalies and may appear in conjunction with a syndromic diagnosis, such as velocardiofacial and Stickler syndromes. PRS is not a syndrome in itself, but rather a sequence of disorders, with one abnormality resulting in the next. Typically, a wide U-shaped cleft palate is also associated with this phenomenon. The smaller mandible displaces the tongue posteriorly, resulting in obstruction of the airway. Infants frequently present at birth with a hypoplastic mandible and difficulty breathing. Pierre Robin sequence (PRS) is classically described as a triad of micrognathia, glossoptosis, and airway obstruction.
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