A gene therapy approach can reverse congenital deafness caused by a genetic defect in mice, according to a preclinical study. The findings potentially present a future treatment for people who are born deaf.
"This is the first time that an inherited, genetic hearing loss has been successfully treated in laboratory mice and as such represents an important milestone for the treatment of genetic deafness in humans," says senior study author Lawrence Lustig of the University of California, San Francisco.
Hearing loss is one of the most common human sensory deficits and results from damage to hair cells in the inner ear. About half of the cases of congenital hearing loss are genetic and caused by genetic defects. Correcting the genetic defects that cause congenital hearing loss could in the future restore hearing. However, previous attempts to reverse hearing loss caused by genetic mutations have not been successful.
Injection of genetic material
Lustig and his team used mice with hereditary deafness caused by a mutation in a gene-coding for a protein called vesicular glutamate transporter-3 (VGLUT3). This protein is crucial for inner hair cells to send signals that enable hearing. Two weeks after the researchers delivered the VGLUT3 gene into the inner ear through an injection, hearing was restored in all of the mice. This improvement lasted between seven weeks and one and a half years after treatment in adult mice and at least nine months when newborn mice received the treatment.
"For years, scientists have been hinting at the possibility of gene therapy as a potential cure for deafness. In this study, we now provide a very real and big step towards that goal," Lustig says.
The study was published in the journal Neuron, July 2012.