Teresa Blankmeyer Burke considers the problematic nature of gene therapy research aimed at eliminating hereditary deafness.
Typically, gene therapy involves combining a therapeutic gene with a vehicle known as a viral vector. This vector is used to deliver the therapeutic gene into a target cell by a process known as transduction. In the case of the inner ear, there is a low transduction efficiency in sensory cells using such viral vectors, including the vector known as AAV1. As a result, there has been variable and inefficient uptake of therapeutic genes.
A recent study in mice, however, published in the journal Molecular Therapy, describes a new method for delivering genes to the sensory hair cells of the inner ear as a potential treatment for deafness. This research describes a new type of viral vector, exo-AAV1, which is more efficient than AAV1 and which may be an effective viral vector for delivering therapeutic genes to treat hereditary deafness by gene therapy.
The use of exosome-associated viruses raises important questions about risks (and unwanted side-effects). There is, for example, the risk of transferring genes that might facilitate the spread of disease through the delivery of genetic material and/or pathogenic proteins. These risks, while important, are not as pressing, however, as the larger issue of whether researchers should conduct research that threatens to eradicate a community.
Members of the signing Deaf community argue that research which aims to eliminate or cure deafness is a form of cultural genocide. The argument goes like this: the use of gene therapy to cure hereditary deafness would result in smaller numbers of deaf children. This, in turn, would reduce the critical mass of signing Deaf people needed for a flourishing community, ultimately resulting in the demise of the community.
This claim is often dismissed as a hyperbolic category mistake. Researchers insist that conducting research on deafness is not a call to eliminate signed language communities or the use of signed language (a language that can be used by hearing people as well as deaf people). More generally, researchers also argue that supporting research to eliminate or treat deafness is not synonymous with supporting discrimination against signing Deaf people.
In my view, discussions about treating hereditary deafness, particularly in children, must consider the genomic integrity and identity of deaf children. The well-being of children who are born deaf is inextricably connected to language acquisition. Indeed, language acquisition (including spoken, signed and written language modalities) confers on deaf children a Deaf way of being in the world. Like any way of being in the world, this has advantages and disadvantages. These advantages, however, are not always obvious to members of the Hearing community.
The majority of deaf children are born to hearing parents in families that have taken up the values and norms of a society constructed for Hearing people. Most of these deaf children are not given a choice about whether to pursue their bimodal and bilingual birthright – that choice is made for them by their culturally Hearing parents.
This bias of Hearing culture can be seen in the normative claim that it is better to be a member of the dominant, mainstream Hearing cultural community than to be a member of the non-dominant Deaf cultural community. This claim is frequently stated but rarely argued for. The usual approach begins with a reference to species typical functioning and then relies on assumptions about the ‘obvious’ value of that which is typical. Yet this assumption about the typical being more valuable that the atypical is problematic and it requires examination.
Gene therapy on deaf children differs from other medical interventions such as cochlear implant surgery in an important regard: deaf children with a cochlear implant are still deaf. Implanted deaf children could, upon reaching adulthood, decide to join the signing Deaf community, and would be welcomed as members based on their experiences of being deaf. Cochlear implant surgery does not close off this life path, even though the children’s parents may not have opted for their children to pursue it.
Deaf children who receive gene therapy to treat their deafness lose this choice permanently, most likely without having had any input into the decision to change their genetic identity – a procedure that fundamentally changes their potential life experiences from those of deaf persons. This different identity is directly linked to their altered genetic make-up.
Concerns about genomic integrity parallel concerns about bodily integrity. It is widely understood that interventions such as limb-lengthening surgery on children of short stature or the surgical alteration of children born with ambiguous genitalia can have profound effects on the well-being of children. The same is true with respect to decisions to alter the genome of children born with hereditary deafness. As such, it is important to consider the potential impact of identity loss on children born with hereditary deafness whose deafness is to be cured by gene therapy.
Teresa Blankmeyer Burke is an Associate Professor of Philosophy at Gallaudet University. @teresaburke