Otoferlin gene: Chinese scientists say some children born deaf can hear after breakthrough gene therapy

A breakthrough therapy trial in China has seen some children in the country who were born entirely deaf now able to hear after partaking in a gene therapy trial, scientists claim. 

The inner ears of the children were fitted with an implant of a harmless virus carrying a new genetic code. According to the MIT Technology Review, the new treatment adds a working copy of the Otoferlin (Otof) gene - a multi-C2 domain protein associated with genetic human deafness. The gene is around 6,000 DNA letters long and had to be broken into two each packaged separately into millions of copies of a harmless virus. 

The children part of the study were born deaf, and researchers from Fudan University in China claimed the experimental treatment has led to four out of five children being able to hear.

Yilai Shu, a surgeon and scientist at Fudan University in Shanghai who is leading the experiment said his treatments began last December, but before that, he spent years developing the techniques involved, testing gene injections in countless mice and guinea pigs. He told the MIT Technology Review: "We were careful, and a little bit nervous, because it was the first in the world". 

Deafness related to Otof is rare and only causes 1-3% of cases of inherited deafness. Around 20,000 people across the US and EU, including the UK, Germany, France, Spain and Italy, may have auditory neuropathy due to malfunctioning versions of the Otof protein.

Several trials are attempting to treat inherited deafness with gene therapy. Addenbrooke’s Hospital in Cambridge is participating in a world-first trial to see whether gene therapy can provide hearing for children with severe to profound inherited hearing loss.

In a statement, Manohar Bance, an ear surgeon at Cambridge University Hospitals said: “Children with a variation in the Otof gene are born with severe to profound hearing loss, but they often pass the newborn hearing screening so everyone thinks they can hear.

“The hair cells are working, but they are not talking to the nerve. Gene therapy for otoferlin deficiency is the right starting point for young children because it’s among – if not the most – simple approaches for treating hearing loss; everything else should be intact and working normally.”