What is Branchio Oto Renal Syndrome

Branchio Oto Renal (BOR) syndrome is a rare genetic condition characterized by the association of branchial arch anomalies, ear malformations, and kidney (renal) abnormalities. It is typically inherited in an autosomal dominant pattern and affects approximately 1 in 40,000 individuals worldwide.

What are the primary features of Branchio Oto Renal syndrome?

Branchio Oto Renal syndrome manifests through a spectrum of symptoms that vary significantly even among family members. The name itself highlights the three main areas of impact: branchial (neck) cysts or fistulas, oto (ear) structures including hearing loss, and renal (kidney) development issues. Within our DiseaseMaps community, 33 people with Branchio Oto Renal syndrome have shared their unique experiences, illustrating how the condition presents differently in every individual.

Which body systems are affected by Branchio Oto Renal syndrome?

The clinical presentation of Branchio Oto Renal syndrome involves several developmental systems:

• Ear anomalies: Structural changes to the outer ear (preauricular pits or tags) and middle or inner ear, frequently leading to conductive, sensorineural, or mixed hearing loss.


• Renal issues: Abnormalities ranging from minor structural variations to renal hypoplasia (underdeveloped kidneys) or agenesis (absence of one or both kidneys).


• Branchial anomalies: The presence of branchial cleft cysts or fistulas, which are small openings or lumps along the side of the neck.

What causes Branchio Oto Renal syndrome?

Branchio Oto Renal syndrome is primarily caused by mutations in the EYA1, SIX1, or SIX5 genes, which provide instructions for proteins essential to the development of the ears, kidneys, and branchial arches during embryonic growth. Because it follows an autosomal dominant inheritance pattern, an individual with Branchio Oto Renal syndrome has a 50% chance of passing the mutation to each of their children.

How is Branchio Oto Renal syndrome differentiated from other conditions?

While several syndromes involve ear and kidney malformations, Branchio Oto Renal syndrome is distinct due to the specific combination of neck cysts and the involvement of the EYA1 gene. Clinicians differentiate it from Branchio-Oto (BO) syndrome by the presence of renal involvement, which is a hallmark diagnostic feature of the Branchio Oto Renal syndrome spectrum.

Next steps

• Consult with a clinical geneticist to discuss testing and family screening.


• Schedule an evaluation with a nephrologist to assess kidney function.


• Obtain a comprehensive audiological evaluation from an otolaryngologist.


• Join the DiseaseMaps community to connect with other patients and caregivers.

Medical disclaimer: This information is for educational purposes only and should not replace professional medical advice, diagnosis, or treatment.

References

• NIH Genetic and Rare Diseases Information Center (GARD): Branchio-oto-renal syndrome.


• Orphanet: Branchio-oto-renal syndrome (ORPHA:130).


• OMIM (Online Mendelian Inheritance in Man): Branchiootorenal Syndrome 1 (#113650).


• National Kidney Foundation: Information on hereditary kidney diseases.