In the UK alone, nine million people are deaf or hard of hearing. In children with hearing loss a common physical sign is an enlarged bony canal in the inner ear, although this doesn’t itself cause deafness. The width of the canal is determined by a tissue called the endolymphatic sac (EES). Mutation in the gene SLC26A4 is linked to EES enlargement and hearing loss. Researchers removed this gene from mice and found it was needed for the EES to absorb fluid. The team imaged the EES of normal mice through development (pictured left to right), showing cells dividing (in red) as it grew. A closer look revealed one set of cells in particular was involved in the transport of ions – a process key to absorbing fluid. Defects in these cells could therefore be what underlies EES enlargement and ultimately hearing loss in children with enlarged bony canals.
Written by Lux Fatimathas