Genetic causes of hearing loss

Abstract
In the past year, genes involved in the branchio‐oto‐renal and Treacher–Collins syndromes were cloned. Myosin 7A, a gene previously implicated in Usher syndrome type 1 B, was also found to be mutated in nonsyndromic hearing loss. Likewise, linkage studies in Pendred syndrome and Usher syndrome type 1 D suggest that allelic mutations can cause syndromic and non‐syndromic forms of deafness. In patients with X‐linked deafness type 3, a hotspot for deletions was found 900 kb proximal to the causal gene POU3F4. Most importantly, the connexin 26 gene is mutated in approximately 50% of all recessive deafness families, enabling early diagnosis and carrier detection. Curr Opin Neurol 11:11–16. © 1998 Rapid Science Ltd