On Hair Cells and Hearing

In a paper published online in advance in PLoS Biology this week, researchers at the Washington University School of Medicine in St. Louis show that Fgf20-knockout mice show hearing loss, and suggest that "FGF20 may also be a deafness-associated gene in humans." Lead author Sung-Ho Huh said in a statement that "this is the first evidence that inner and outer hair cells develop independently of one another," adding that "this is important because most age-related and noise-induced hearing loss is due to the loss of outer hair cells." WashU's David Ornitz adds that "in mice, the precursor cells that can become outer hair cells must be exposed to the FGF20 protein at an early stage. After embryonic day 14, it doesn’t matter if they see the protein. It's too late for them to become outer hair cells." Ornitz also says that a team at Baylor College of Medicine is sequencing the DFNB71 region of the genome in search of FGF20 mutations that may play a role in human deafness.