Treacher Collins-Franceschetti Syndrome (Mandibulofacial Dysostosis)

Synonyms

Franceschetti-Zwahlen-Klein syndrome; Mandibulofacial dysostosis; Treacher Collins syndrome

Definition

Treacher Collins-Franceschetti syndrome (TCFS) was first described in 1900 and is an autosomal dominant condition that is characterized by general craniofacial soft tissue and skeletal hypoplasia of the first and second branchial arches, with a wide spectrum of deformities.

Etiology

The disorder is caused by a mutation in the TCOF gene on chromosome 5q32-33.1, which encodes the treacle protein. Deletions in this gene cause haploinsufficiency in an autosomal dominant genotype, with deficiencies in ribosomal DNA transcription causing increased apoptosis of neural crest cells.

Clinical Presentation

The primary feature of TCFS is mandibular retrognathia, soft and hard tissue malar deficiency, downward-slanting palpebral fissures, euryblepharon with or without coloboma, and conductive hearing loss. The orbital region is characterized by hypoplasia of the superior and inferior...