BOR syndrome is an autosomal dominant disorder that variably involves developmental defects of ear, brachial arches, and kidney. The disease is caused by mutations in two functionally related genes EYA1 and SIX5.
Incidence of BOR syndrome is estimates 1 in 40,000, which includes both forms wheras BOR1 holds the major share.[Error: Macro 'ref' doesn't exist]
Clinical presentation of BOR syndrome is variable. Hearing loss may be sensorineural, conductive, or mixed and is caused by outer, middle, or inner ear anomaly. Branchial fistulas or cysts can be present. Distubances in lacrimation may occur as a result of aberrant innervation. Renal dysplasias vary from normal to severe functional disturbances the manifest antenatally already by oligohydramnios.
Branchiootorenal dysplasia deafness is of a mixed (conductive and sensorineural) type because of malformations (atresia to stenosis) of the external auditory canal and nderdeveloped cochlea and semicircular canals, respectively.
Melnick M et al. (1976) Familial branchio-oto-renal dysplasia: a new addition to the branchial arch syndromes.[^]
Chang EH et al. (2004) Branchio-oto-renal syndrome: the mutation spectrum in EYA1 and its phenotypic consequences.[^]
Fraser FC et al. (1978) Genetic aspects of the BOR syndrome--branchial fistulas, ear pits, hearing loss, and renal anomalies.[^]
Cremers CW et al. (1980) The earpits-deafness syndrome. Clinical and genetic aspects.[^]
Fraser FC et al. (1980) Frequency of the branchio-oto-renal (BOR) syndrome in children with profound hearing loss.[^]
Abdelhak S et al. (1997) Clustering of mutations responsible for branchio-oto-renal (BOR) syndrome in the eyes absent homologous region (eyaHR) of EYA1.[^]