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Otodental syndrome is a very rare inherited condition characterized by grossly enlarged canine and molar teeth (globodontia) associated with sensorineural hearing loss.
ORPHA:2791Classification level: Disorder
Prevalence of this disorder is not known. It has been described in about 10 families of European, Chinese and Brazilian descent.
Patients have striking pathognomonic dental features characterized by globodontia of the primary and secondary dentition, sparing the incisors. Missing teeth, especially premolars, are also reported. Due to abnormal crown morphology, there is a great propensity to formation of caries. There is a high rate of endodontic-periodontic lesions due to the aberrant coronal and pulpal morphology. The dental conditions are associated with bilateral sensorineural high-frequency hearing deficit with an age of onset that varies from early childhood to middle age. Variable facial dysmorphism has also been reported. One family was found to have an associated bilateral iris and retinal ocular coloboma.
Haploinsufficiency in the fibroblast growth factor 3 (FGF3) gene (11q13) has been reported in patients with otodental syndrome and is thought to cause the phenotype. In the family with the associated ocular coloboma, a microdeletion in the Fas-associated death domain (FADD) gene (11q13.3) was found to be responsible for ocular features.
The dental findings are diagnostic. Molecular genetic testing confirms the diagnosis.
Although the association of sensorineural hearing loss and dental anomalies can be found in other syndromes, none display the striking dental manifestations of otodental syndrome.
The condition appears to be inherited in an autosomal dominant manner with complete to variable penetrance and variable expressivity. Genetic counseling should be offered to affected families.
Management and treatment
Dental management is complex, interdisciplinary and requires regular follow up, scheduled tooth extraction and eventually orthodontic treatment. Monitoring of hearing and, if necessary, hearing aids are mandatory. A preventive program is mandatory in order to maintain proper oral hygiene and health. Endodontic therapy can be difficult due to duplicated pulp canals in the affected posterior teeth. Multiple extractions may be needed and fixed or removable prostheses should be constructed. Implants are also a potential consideration.
The functional prognosis is mostly good with appropriate dental treatment and hearing aids. Quality of life may be affected by psychological and functional aspects.