Craniofrontonasal dysplasia is an X-linked malformation syndrome characterized by facial asymmetry (particularly orbital), body asymmetry, midline defects (hypertelorism, frontal bossing, broad grooved or bifid nasal tip, cleft lip and/or palate, high arched palate), skeletal anomalies (clavicle pseudoarthrosis, coronal craniosynostosis, various digital and limb anomalies including syndactyly, clinodactyly of the 5th finger, broad thumbs) and ectodermal dysplasias (dental anomalies, grooved nails, wiry hair). Contrary to most X-linked disorders, females are much more severely affected whereas males are asymptomatic or present with a mild phenotype, frequently only displaying hypertelorism.

The two portions of the clavicle (corresponding to the two primary ossification centers of the clavicle) are connected by a fibrous bridge that is contiguous with the periosteum, and a synovial membrane develops, resulting in a clavicle with a bipartite appearance radiographically. Congenital pseudarthrosis of the clavicle generally presents as a painless mass or swelling over the clavicle.