Robin sequence, also called Pierre Robin syndrome or Pierre Robin anamaloid, is a congenital condition characterised by facial abnormalities. Its aetiology has no genetic base, but rather, is reliant on a sequence of events, one following the other.
Robin sequence is the preferred term rather than Pierre Robin syndrome, as most cases are not syndromic 4.
Robin sequence occurs in 1 in 8500 neonates 3.
May present with upper airway obstruction, sleep disturbance or apnoea.
The primary defect is a retrognathic mandible which occurs at 7-11 weeks of gestation. This prevents the tongue from descending which in turn prevents fusion of palatal shelves resulting in glossoptosis (retraction of tongue), high or U-shaped palate and airway obstruction. It is characterised by
Most cases tend to be sporadic.
A sagittal fetal facial profile may show severe micrognathia. Ancillary sonographic features include
- polyhydramnios: from impaired swallowing from micrognathia
Severe micrognathia may lead to
- obstruction of fetal swallowing: may in turn cause polyhydramnios
- airway obstruction: may, in turn, lead to postnatal hypoxia
- 1. Lachman RS, Ṭaybi H. Taybi and Lachman's radiology of syndromes, metabolic disorders, and skeletal dysplasias. Mosby Inc. (2007) ISBN:0323019315. Read it at Google Books - Find it at Amazon
- 2. Entezami M, Albig M, Knoll U et-al. Ultrasound Diagnosis of Fetal Anomalies. Thieme. (2003) ISBN:1588902129. Read it at Google Books - Find it at Amazon
- 3. Hagberg CA. Benumof's airway management. Mosby. ISBN:0323022332. Read it at Google Books - Find it at Amazon
- 4. Abramson ZR, Peacock ZS, Cohen HL et-al. Radiology of Cleft Lip and Palate: Imaging for the Prenatal Period and throughout Life. Radiographics. 2015;35 (7): 2053-2063. doi:10.1148/rg.2015150050 - Pubmed citation