Introduction Frontonasal dysplasia (FND) consists of a group of disorders characterized by ocular hypertelorism, midline facial cleft affecting the nose and/or upper lip and palate, notching or clefting of the alae nasi, and it is sometimes associated with anterior cranium bifidum and other malformations (Wu et al. 2007; Kayserili et al. 2009; Twigg et al. 2009). Although it has long been recognized that FND results from abnormal development of the embryonic frontonasal prominence, which forms from cranial neural crest cells populating in between the forebrain and surface ectoderm and ultimately gives rise to the forehead, nose, philtrum, and premaxillary component of the upper jaw, the causes and molecular mechanisms of FND pathogenesis are not well understood (Farlie et al. 2016). Mutations in 5 genes, including ALX1, ALX3, ALX4, EFNB1, and ZSWIM6, have been identified in a small number of patients with FND disorders (