American scientists have restored hearing and balance for the first time in adult mice with the genetic form of deafness DFNA41, which is analogous to the human condition.
The method is based on CRISPR-Cas9 technology and the delivery of editing molecules into inner ear cells using the safe viral vector AAV2. The uniqueness of the approach lies in its precise action on only the defective section of the P2RX2 gene, without changing its healthy copy. A single injection was enough for the mice to regain hearing and recover vestibular function. Moreover, their auditory cells became less vulnerable to damage from loud sounds.
The safety of the procedure was confirmed by genetic analysis, and its effectiveness was additionally tested on human stem cells with the same mutation. This is the first case of successful long-term treatment of late-onset deafness in adults. Until now, gene therapy for hearing had been developed mainly for infants with congenital deafness. The new approach shows that treatment is possible even for late-appearing forms of the disease. It also opens the way to personalized treatment of other forms of inherited hearing loss in adults.
