Clinical Guidance

Branchiootorenal spectrum disorder (BORSD) is characterized by second branchial arch anomalies (e.g., preauricular pits and branchial cleft sinuses or cysts) and malformations of the outer, middle, and inner ear associated with conductive, sensorineural, and/or mixed hearing impairment. Congenital anomalies of the kidney and urinary tract (CAKUT) include kidney agenesis, hypoplasia, and dysplasia as well as urinary tract anomalies such as ureteropelvic junction (UPJ) obstruction, calyceal cysts and/or diverticula, and/or vesicoureteral reflux (VUR). Glomerular pathology that includes proteinuria and glomerulosclerosis has been reported. Some individuals progress to end-stage kidney disease (ESKD) depending on the severity of the kidney involvement.

Source: GeneReviews — "Branchiootorenal Spectrum Disorder"

Differential Diagnosis

At the time of this writing, Online Mendelian Inheritance in Man (OMIM) lists more than 700 entries for syndromic forms of hearing loss. Although branchiootorenal spectrum disorder (BORSD) has a distinctive phenotype that is readily appreciated when segregating in large families, the diagnosis can be difficult to establish in small families. Possible considerations in a differential diagnosis are shown in .

Table 2.

Genes of Interest in the Differential Diagnosis of Branchiootorenal Spectrum Disorder

Gene(s) | Disorder | MOI | Features of Disorder

Overlapping w/BORSD | Distinguishing from BORSD

CHD7 | CHD7 disorder (incl CHARGE syndrome) | AD | Hearing loss, external/middle/inner ear anomalies, kidney anomalies | Coloboma, choanal atresia, genital hypoplasia, developmental delay

COL4A3

COL4A4

Source: GeneReviews — "Branchiootorenal Spectrum Disorder"

Clinical Guidance

Hearing loss. Individuals with hearing loss should avoid environmental exposures known to cause hearing loss. Most important for persons with mild-to-moderate hearing loss is avoidance of repeated overexposure to loud noises, particularly secondary to earbud use. The headphone safety feature built into most smartphones can be set to a maximum limit of 75 decibels (dB). Headphone/earbud safety features can be found in the phone settings menu:

• In iPhones, under Settings Sounds Haptics Headphone Safety

• In Android phones, under Settings Sounds Vibrations Volume Media volume limit

Also see these general resources on noise reduction:

• 6 Simple Ways to Check If Your Headphones Are Too Loud

• How Do I Prevent Hearing Loss from Loud Noise?

Anecdotal reports that increased intracranial pressure in individuals with enlarged vestibular aqueduct (EVA) can occasionally trigger a decline in hearing has led some providers to recommend avoiding activities such as weightlifting and contact sports ; however, evidence is insufficient to support the claim that avoiding these activities will decrease the risk of overall hearing loss progression .

Source: GeneReviews — "Branchiootorenal Spectrum Disorder"

Therapies Under Investigation

Search ClinicalTrials.gov in the US and EU Clinical Trials Register in Europe for information on clinical studies for a wide range of diseases and conditions. Note: There may not be clinical trials for this disorder.

Source: GeneReviews — "Branchiootorenal Spectrum Disorder"