Craniofrontonasal syndrome (CFNS) is a rare X-linked dominant disorder characterized by a more severe phenotype of multiple skeletal malformations in heterozygous females in contrast to no or mild clinical features in hemizygous males. Females typically display craniofacial asymmetry, marked hypertelorism with a central nasal groove, bifid nasal
tip, coronal craniosynostosis (unilateral or bilateral), corpus callosum agenesis, thick wiry hair, and occasionally cleft lip and/or palate. Extracranial features include sloping shoulders with dysplastic clavicles, asymmetry of the thoracic skeleton and pectoral muscle, unilateral breast hypoplasia, longitudinally grooved fingernails, mild cutaneous syndactyly, and umbilical and diaphragmatic hernia. Hemizygous males have no or only mild manifestations such as hypertelorism and less frequently cleft lip and/or palate.