Pierre Robin Sequence: Controversies in Management

Multiple factors contribute to the Pierre Robin sequence (PRS), also called Pierre Robin syndrome. Hypoplasia of the mandible before the ninth week of development is assumed to be the underlying cause in most cases. The tongue blocks the space between the palatal shelves when they develop until about week 8. The palatal shelves fuse once the tongue is retracted between the tenth and eleventh weeks of development. Hypoplasia of the mandible in the Pierre Robin sequence causes the tongue to shift backward, preventing the palate from closing. The Pierre Robin sequence has a mysterious origin. Chin growth restriction during pregnancy due to oligohydramnios, myotonia, or connective tissue disease are all possible causes. In most cases, the Pierre Robin sequence occurs in isolation. However, in rare instances (37% in one cohort of 74 individuals), numerous abnormalities develop as part of a syndrome. About a third of those with congenital anomalies also suffered from Stickler or velocardiofacial syndrome (VCFS). Therefore, developmental misexpression of SOX9 (sex-reversed Y chromosome [SRY]-box 9), a transcription factor crucial for sex and skeletal development, might account for some occurrences of Pierre Robin sequencing. Because of the correlation between Stickler syndrome and VCFS, patients with the Pierre Robin sequence should undergo ophthalmologic testing and a fluorescence in situ hybridization (FISH) study to look for chromosome 22 deletion.