ABSTRACT
The occurrence of branchial anomalies was first recognized in the early nineteenth century (1) and thereafter additional reports were published about the association between ear anomalies and cervical fistula (2-5). However, the first report of a family with associated kidney problems did not appear until 1967 (6). Since then a great deal of progress has been made in clinical delineation and genetics of branchial anomalies (715). The hearing loss associated with branchial anomalies is variable; it can be progressive or stable or sensorineural or conductive; an illustrative example was a patient who had sensorineural hearing loss in one ear and conductive hearing loss in the other ear (16). Variable abnormalities associated with the external ear (malformed pinna, preauricular pits), middle ear (malformed ossicles), and inner ear (abnormal semicircular canal and cochlea) have also been reported (7, 10, 11, 17-24). In each ear the hearing loss can vary from mild (20-40 dB loss) to moderate (40-60 dB) and to most severe (60-80 bB) or profound loss (>80 dB). The cochlea is normally coiled in a spiral of 2-1/2 turns; however, patients with branchio-oto-renal (BOR) syndrome frequently have Mondinitype cochlear malformations, where cochlea is reduced to 1-1/2 turns (9). The penetrance of the disease gene appears to be 100% in persons carrying causative mutations. However, the clinical expression of BOR syndrome genes is extremely variable, and the phenotype can differ significantly within and between families. The major clinical features are hearing loss with pinnae deformities and preauricular pits, branchial arch anomalies, and renal defects (9, 13, 23, 25, 26). In most persons with BOR syndrome, auricular deformities, preauricular pits, ossicular mal-formations, and cervical sinuses/cysts/fistula occur together, reflecting the embryological origin of these structures from the first and second branchial arches.
