Branchio-oto-renal syndrome

Autosomal dominant - en

Branchio-oto-renal (BOR) syndrome is a genetic disorder that affects the development of the tissues in the neck, the ears, and the kidneys. It is a rare condition that is present from birth and can vary widely in its severity and manifestations among affected individuals. The syndrome is characterized by the presence of branchial cleft cysts or fistulas, hearing loss, and renal anomalies. This article provides an overview of BOR syndrome, including its symptoms, causes, diagnosis, and management.

Symptoms

The symptoms of BOR syndrome can vary significantly from person to person. The most common features include:

• Branchial anomalies: These are defects in the development of the tissues in the neck, which may lead to branchial cleft cysts or fistulas.
• Otic anomalies: Hearing loss, which can be conductive, sensorineural, or mixed, is a common feature. Other ear abnormalities may include preauricular pits, malformed ears, or ear tags.
• Renal anomalies: These can range from mild renal hypoplasia to complete renal agenesis. Some individuals may have only minor urinary tract anomalies, while others may experience significant kidney dysfunction.

Causes

BOR syndrome is caused by mutations in several genes, with the most common being mutations in the EYA1, SIX1, and SIX5 genes. These genes play crucial roles in the development of the ears, kidneys, and branchial arches. The condition is inherited in an autosomal dominant pattern, meaning that only one copy of the altered gene in each cell is sufficient to cause the disorder. There is a 50% chance of passing the mutated gene to offspring.

Diagnosis

Diagnosis of BOR syndrome is based on clinical evaluation and the presence of characteristic features. Genetic testing can confirm the diagnosis by identifying mutations in the EYA1, SIX1, or SIX5 genes. Prenatal diagnosis may be available for families with a known mutation.

Management

Management of BOR syndrome is multidisciplinary and focuses on the specific symptoms present in each individual. Treatment may include:

• Surgical intervention: For branchial cleft cysts or fistulas, and for certain types of hearing loss.
• Hearing aids or cochlear implants: To address hearing loss.
• Regular kidney monitoring: To assess kidney function and manage any renal anomalies.
• Genetic counseling: To provide information and support for affected individuals and their families.

Prognosis

The prognosis for individuals with BOR syndrome varies depending on the severity of the symptoms. With appropriate management, most individuals can lead normal, healthy lives. However, those with significant kidney disease may have a poorer prognosis.