Mandibulofacial dysostosis

Mandibulofacial dysostosis, also known as Treacher Collins syndrome (TCS) or Treacher Collins-Franceschetti syndrome, is a rare genetic disorder that primarily affects the development of bones and other tissues of the face. The condition is present at birth and results from abnormal development of the first and second pharyngeal arches during early embryonic growth. Key clinical features include underdevelopment of the facial bones, particularly the mandible (lower jaw) and zygomatic bones (cheekbones), giving the face a characteristic appearance with a small jaw (micrognathia) and flattened cheeks. Patients frequently have downward-slanting palpebral fissures (eye openings), colobomas (notches) of the lower eyelids, and sparse or absent eyelashes on the lower lids. The external ears are often malformed, small, or absent (microtia or anotia), and conductive hearing loss is common due to abnormalities of the middle ear ossicles and external auditory canals. The severity of mandibulofacial dysostosis varies widely, even among affected members of the same family, ranging from mild cases that may go undiagnosed to severe presentations with significant airway compromise requiring urgent intervention at birth. Cleft palate occurs in approximately one-third of affected individuals. Intelligence is typically normal. The condition primarily affects the craniofacial skeleton, the eyes, and the auditory system. Treatment is multidisciplinary and symptomatic, as there is no cure. Management may include surgical reconstruction of the facial bones, jaw, and ears; hearing aids or bone-anchored hearing devices to address hearing loss; cleft palate repair; and orthodontic treatment. In severe cases, tracheostomy or mandibular distraction osteogenesis may be necessary to secure the airway in the neonatal period. Speech therapy and psychosocial support are also important components of care. Genetic counseling is recommended for affected individuals and their families.

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