BOR syndrome

Branchio-Oto-Renal (BOR) syndrome, also known as Melnick-Fraser syndrome or branchio-oto-renal dysplasia, is a rare genetic disorder characterized by a combination of branchial arch anomalies, hearing loss, and renal (kidney) malformations. It is one of the most common syndromic forms of hearing loss, accounting for approximately 2% of profoundly deaf children. The condition affects multiple body systems, primarily the ears, neck, and kidneys. The hallmark features of BOR syndrome include branchial cleft cysts, sinuses, or fistulae (abnormal openings or passages in the neck); hearing loss that may be conductive, sensorineural, or mixed; preauricular pits or tags; structural malformations of the outer, middle, or inner ear; and renal anomalies ranging from mild hypoplasia to complete absence of one or both kidneys (renal agenesis). The severity and combination of features vary widely, even among affected members of the same family. When kidney malformations are absent, the condition is sometimes referred to as Branchio-Otic (BO) syndrome. BOR syndrome is most commonly caused by mutations in the EYA1 gene on chromosome 8q13.3, though mutations in SIX1 and SIX5 genes have also been identified in some families. There is currently no cure for BOR syndrome, and management is supportive and symptom-directed. Treatment may include hearing aids or cochlear implants for hearing loss, surgical correction of branchial fistulae or cysts, and monitoring and management of renal function. Regular audiological and nephrological follow-up is essential, particularly in childhood, to detect and address complications early. Genetic counseling is recommended for affected individuals and their families.

Common questions about BOR syndrome