Are CRISPR researchers actually just tone-deaf?

The controverial gene-editing method could save lives, but do the ends justify the risky means?

Article Thumbnail

Image Credit: Виталий Смолыгин

Going deaf may not be a concern for many students, but the implications are far-reaching for those that are. As well as the direct impact of losing one’s hearing, diseases that impact hearing loss often present other challenges: psychological strain and social difficulty both hit young people with hearing loss particularly hard. Luckily, for those that have lost their hearing due to genetic defects, there may be a solution on the horizon, through a revolutionary form of gene editing currently being used to treat a variety of genetic issues.

CRISPR-Cas9, or ‘clustered regularly interspaced short palindromic repeats’ is a simple but incredibly powerful method of gene editing. It uses the normal ability of bacteria to chop up the DNA of attacking viruses to re-assemble DNA in human embryos.

Although the actual process had long been invisible to scientists due to the tiny size of the DNA molecules, a team of researchers at Kanazawa University and the University of Tokyo were able to observe CRISPR working for the very first time in 2017 using a method known as atomic force microscopy.

The 30-second editing process shows the CRISPR-Cas9 enzyme chomping down on a single strand of DNA. Once that DNA has been separated, scientists can use the human cell’s own DNA production ability to add, or repair certain sections to encourage traits that have been lost due to genetic diseases. Patients with Alport Syndrome, for example, lack collagen-4, giving them issues with their kidneys, eyes, and ears. Gene editing of Alport-affected embryos could, at least in theory, allow patients who would otherwise have developed these issues to live normally.

Of course, as with any genetic editing method, there are ethical issues that come with meddling with CRISPR. Last November, Chinese scientist He Jiankui prompted international outcry amongst the scientific community when he announced the birth of twin girls he says he had made resistant to HIV (the claim has yet to be verified by independent genomic research.) Scientists argued that the benefits of resistance to HIV (an unnecessary precaution considering it only existed in the girls father) were far outweighed by the unknown impact of DNA editing on the girls in later life.

This has not stopped Russian scientist Denis Rebrikov from beginning to edit genes in human embryos that could alter a recessive ‘deaf gene’ common to people in Siberia. He argues that he has met the requirements set out in a statement by scientists last year arguing that gene editing had to be justified by a “compelling medical need,” and an “absence of reasonable alternatives.” Rebrikov told Nature that he does not plan to implant edited embryos until he gets regulatory approval for the practise.

Gene editing, for deaf people, presents another pressing question. There remains a somewhat controversial discussion in the community about the risks of gene editing erasing the culture that has surrounded deafness for years. Many don’t see deafness as a disability at all, and there are others that want to preserve the rich linguistic history of sign language and lip-reading. There are likely over 250 sign languages used worldwide, with their own culture, personalities, and increasingly developed syntax. The questions remains: considering deafness isn’t life-threatening, and hearing aids are getting better all the time, does the goal of curing hearing loss justify the risks behind the process?

Latest in Science