An 11 year old boy who could only use self-invented sign language to communicate from birth, had his hearing restored after receiving the Eli Lilly’s sponsored otoferlin gene therapy.
A young boy from Morocco who grew up never hearing had his hearing restored after a trial gene therapy. Aissam Dam, an 11 year old boy, who had no formal education could only communicate using self invented sign language.
His deafness was a congenital one, caused by a single mutation in the otoferlin gene. There are other causes of congenital deafness. However, otoferlin deafness affects about 200,000 people worldwide.
Genetic hearing loss accounts for 50% of all cases of hearing loss, but otorferlin-related deafness is rare. The mutated otoferlin gene destroys a protein in the inner ear’s hair cells that are necessary for the transmission of sound to the brain. Other causes are acquired and could be caused by infection, trauma, noise exposure, and ototoxicity.
Aissam’s relieve came as his family sought a hearing specialist for him after he moved to Spain with his family. He was considered for a trial gene therapy that was intended to replace the mutated otoferlin gene with a functional one. Although doctors were skeptical about the success rate of the therapy, it turned out that the boy’s hearing was restored after the therapy.
According to New York Times “On Oct. 4, Aissam was treated at the Children’s Hospital of Philadelphia, and is the first person to receive gene therapy in the United States for congenital deafness. Although the intended result was for his hearing to be restored, the outcome of the clinical trial was still doubtful.
The outcome of the gene therapy was stunning, as he could hear all sounds after the therapy. This impressive outcome raises hope for other patients with congenital hearing loss.
Doctors intend to sign up more younger patients to further evaluate the efficacy of the therapy. It is widely believed that Aissam’s treatment success could pave for more gene therapies to target other forms of congenital deafness and other congenital conditions.
Mutation of otoferlin gene in humans may give rise to Auditory Neuropathy Spectrum Disorders. According to Korver et al. (2017), “Auditory Neuropathy Spectrum Disorder may be caused by a primary lesion located in the inner hair cells, in the auditory nerve of intervening synapse and may also include damage to neuronal populations in the auditory pathway”
According to experts, the complex nature of the inner ear is such that ear targeted gene therapy may not affect cells of other parts of the body. But the main issue is that cochlear labyrinth is complex fluid-filled region that requires skillful manipulation for therapy delivery.
“Restoration of hearing is achieved by implantable or non-implantable hearing devices, including conventional hearing aids, cochlear implants and bone-anchored hearing aids” Korver et al. (2017) reports.
Babies eligible for the gene therapy were children with no cochlea implants. Babies born with otorfelin deafness often receive cochlear implants. Aissam had no cochlear implant and was a suitable candidate for the therapy.
The Food and Drug Administration permitted the study on the grounds that researchers should begin with older children and should only treat one ear at a time.
According doctors, Aissam’s results were remarkable. The Eli Lilly supported gene therapy to restore hearing has now gained more attention after Aissam’s success and have advanced the treatment to much younger children.
The report of effectiveness and safety of the gene therapy will definitely spark interests in other genes.
References
Korver AM, Smith RJ, Van Camp G, Schleiss MR, Bitner-Glindzicz MA, Lustig LR, Usami SI, Boudewyns AN. Congenital hearing loss. Nat Rev Dis Primers. 2017 Jan 12;3:16094. doi: 10.1038/nrdp.2016.94. PMID: 28079113; PMCID: PMC5675031.
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