Prenatal diagnosis of Treacher Collins syndrome: A case report and literature review.

Treacher Collins syndrome (TCS) should be suspected if the triad of micrognathia, glossoptosis, and posterior cleft palate, and deformed external ears are observed during prenatal ultrasonography, excepting Pierre Robin sequence. Visualization of the fetal zygomatic bone and down-slanting palpebral fissures are conducive to differentiation. Molecular genetics testing can establish a definite diagnosis. A 28-year-old pregnant Chinese woman was referred for systematic ultrasound examination at 24 weeks. Two-dimensional and three-dimensional ultrasound showed polyhydramnios, micrognathia, absence of nasal bone, microtia, secondary cleft palate, mandibular hypoplasia, glossoptosis, and normal limbs and vertebrae. Pierre Robin sequence was misdiagnosed with the triad of micrognathia, glossoptosis, and posterior cleft palate. Final diagnosis of TCS was confirmed by whole-exome sequencing. Visualization of the fetal zygomatic bone and down-slanting palpebral fissures can facilitate a differential diagnosis between Pierre Robin sequence and TCS, with the triad of micrognathia, glossoptosis, and posterior cleft palate.