Because nearly half of the world's population may lose some or all ability to hear by the age of 80, finding out why this occurs is a priority. The latest findings are the isolation of two genes which, when mutated, both cause hearing problems. The first encodes a protein called diaphanous, which is involved in functioning of sensory hair cells in the cochlea. The second encodes a putative sulphate transporter protein — pendrin — that is mutated in patients with a hearing disorder called Pendred syndrome. Defects in pendrin affect the growth and development of the cochlea.
