Mandibulofacial Dysostosis is a disorder characterized by deformities of the facial bones and skull. It is a rare type of syndrome which is inherited as an autosomal dominant disease. The condition generally presents with a narrow face, small lower jaw and lack of prominent cheek bones. The condition is present since birth and may be associated with other anomalies involving the ears, eyelids, palate and throat. The condition is chiefly associated with underdevelopment of facial bone structure. It is also known as Treacher-Collins syndrome and Treacher Collins-Franceschetti syndrome.
Causes of Mandibulofacial Dysostosis
Mandibulofacial dysostosis is an inherited disease associated with a genetic mutation. The disease has no specific predilection for any race and is found affecting males and females equally. The gene mutation is caused by defect in TCOF1 gene. Parents with mutated genes transmit the disease to their offspring. The disease may be very mild or undiagnosed in the parent in some cases.
The disease occurs in around 1 of every 25,000 to 50,000 births. The disease shows more severe symptoms in subsequent generations in a family suffering from mandibulofacial dysostosis. The syndrome manifest at birth and can be diagnosed by clinical symptoms, X-rays, ultrasounds and CT scans.
The severity of the symptoms of mandibulofacial dysostosis varies in different patients. The characteristic facial structure is similar in most of the patients with various degrees of deformity. The face is narrow at the lower third due to narrow and small lower jaws. The chin is retruded with presence of a prominent notch. The small size of jaws leads to orthodontic problems such as malocclusion.
Other dental problems include absence of teeth or malformed tooth enamel. In one-third of mandibulofacial dysostosis cases cleft palate is present. Absence of salivary glands such as parotid glands may also be associated with the disease. A notch like depression is present on the lower aspect of eyelids. The eyelashes are scanty or absent in most of the cases. Loss of vision can occur in severe cases with eye deformity. Defects in nasal bones may also be present.
Both inner and outer ears are deformed in mandibulofacial dysostosis. The pinnae are deformed with or without extra ear tags. Defects in the inner ear can lead to deafness. Presence of hypoplastic pharynx and narrowed wind pipe associated with mandibulofacial dysostosis can be lethal in infants. The condition can lead to difficulty in feeding and breathing.
Mild forms of mandibulofacial dysostosis may not require specific treatment except for correction of dental problems and improvement of overall deformed structures. In cases with moderate to severe deformities surgical approaches are preferred to restore the aesthetics. Cosmetic surgeries for facial reconstruction are advised in severely deformed cases. Various surgeries involving eyes, cheek bone, jaws can be performed at specific ages when the bones fully develop.
Cases with cleft palate should be treated with separate surgical procedure at an early age for closure of the cleft. Orthognathic surgeries are also indicated to correct severe orthodontic problems in adult life. The children with feeding and respiratory problems require immediate attention and may require surgical approaches to maintain the airway.