A new deafness gene

A three year project grant was awarded to Professor Karen Steel at the Sanger Genome Institute to carry out a study looking for a new gene associated with deafness.

[Project grant, 2004-2007]

The objective of the research was to identify the gene mutated in diminuendo, a mouse mutant that has progressive hearing loss. The additional aims were to determine what the function of the gene is, where it is expressed and to examine the development of the sensory hair cells in the mutant to define the structural problem.

After over two years of genetic analysis, the causative mutation was identified as a single base pair change in the microRNA gene miR-96. MicroRNAs are small stretches of about 20 bases of RNA that bind to target sites in many other genes and reduce their activity, MicroRNAs are a difficult class of genes to study; they are regulators, and so their effects are mediated through a number of different genes, any one or more of which may be causing the hearing loss.

MicroRNA's are also a relatively new discovery, so there is a lot that is not understood about their regulation and modes of action, and how they are produced and processed. Mutations have also been found in the human version of the same microRNA in families with progressive hearing loss showing that this new type of gene is also important to human disease.

This is a novel and significant finding providing evidence of the involvement of a new type of genetic mutation in hearing loss.