Branchio-otic syndrome

Branchio-otic syndrome (also known as BOSBOS1, BO syndrome 1 and branchiootic dysplasia) is a rare autosomal dominant disease. It manifests as abnormalities of the second branchial arch, with predominant abnormalities of the ear. No renal disease is seen, in contradistinction to its close namesake branchio-oto-renal dysplasia (BOR), with which there is broad overlap in clinical presentation, pathogenesis and management approach 1.

The incidence of branchio-oto-renal dysplasia is 1 in 40,000 births, and therefore branchio-otic syndrome is somewhat less than this 1.

The primary abnormalities are secondary to maldevelopment of the 2nd branchial arch 1.

Absence of renal abnormalities: if present then the diagnosis is branchio-oto-renal dysplasia.

Mutations in the EYA1 and SIX1 genes are found in branchio-otic syndrome 1. Penetrance is fairly high, but not complete, with both intra- and inter-family variability in its clinical severity 1.

Share article

Article information

rID: 74067
Section: Syndromes
Synonyms or Alternate Spellings:
  • Branchiootic syndrome (BOS)
  • Branchio-otic dysplasia
  • Branchio otic dysplasia
  • Branchiootic dysplasia
  • BO syndrome 1
  • BOS1
  • Branchio otic syndrome

Support Radiopaedia and see fewer ads

Updating… Please wait.

 Unable to process the form. Check for errors and try again.

 Thank you for updating your details.