New gene mutation linked to congenital deafness

Researchers have identified mutations in a gene called CDC14A that impair the function of kinocilia, which are specific cilia of sensory cells inside the inner ear, resulting in severe to profound congenital deafness¹. 

By sequencing the genomes of afflicted Iranian and Mauritanian individuals, the biologists, including Yosra Bouyacoub from the Institut Pasteur de Tunis, Tunisia, discovered the mutated gene.

The gene is expressed in the hair cells of cochlea, a fluid-filled snail-shell-like sensory organ in the inner ear. 

Inactivating the corresponding gene in zebrafish embryo generated abnormally short kinocilia, suggesting that CDC14A gene controls the growth of kinocilium.  

In cochlea, fibrous structures link the kinocilia to bundles of hair cells. Mutations in CDC14A, however, can disrupt the links between hair bundle and kinocilium, producing abnormal hair bundles. 

This, in turn, affects signal transmission through the hair cells, suggesting that the deafness is caused by abnormally short kinocilia, the researchers conclude.  

“This research will help us understand the basic mechanisms underlying normal hearing, the pathophysiology of various deafness forms and improve the techniques of molecular diagnosis for deafness,” says principal investigator Christine Petit from the Institut Pasteur, France. 

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