In the last few years, scientists have discovered and implemented a new technique that allows us to target and replace faulty genes with healthy ones. The CRISPR/Cas 9 system, alongside a handful of other techniques, has been used to correct a bone marrow gene in a patient who had severe combined immunodeficiency and in Parkinsons patients who’ve had skin cells turned into stem cells, repaired with the technique, then turned into neurons.
In these experiments, the edited cells lived and functioned normally in the petri dish, but weren’t reintroduced into the patients’ bodies. But that will be coming soon, according to Washington University systems biologist Michael White in Pacific Standard:
Next-generation gene therapies will first be aimed at diseases such as AIDS and leukemia, because those diseases involve cells that can be easily removed, edited, and then put back. But as newer editing systems like CRISPR/Cas9 develop, we’ll be able to do more gene edits in other parts of the body. In March, researchers at MIT reported that they were able to correct a gene in the liver cells of mice, by injecting CRISPR/Cas9 components into the blood stream.
So far, these techniques are effective on diseases caused by a single mutation that stops a single gene function. For example, Phenylketonuria, where the single mutation causes the inability to break down the dietary amino acid phenylalanine. More complex diseases, like obesity and Type 2 diabetes, are not likely contenders because many genes working together control the risk and development of the conditions.
These CRISPR cases are clear cut; who wouldn’t want to cure AIDS or repair the immune system of a boy who would otherwise die. But our culture will likely encounter a time when the medical necessity of a condition might be debatable. Social scientists have shown that some traits like height and athleticism and maleness all benefit an individual’s earning power, treatment by others and value in society over time. Some parents could argue that changing their children’s genetics to promote these traits would give them a better life, much like treatment of disease would benefit others. White writes:
In an effort to understand human genetics, researchers are compiling catalogs of small genetic changes that, in some cases, can have a big impact. DNA edits that boost athletic performance wouldn’t be beyond the resources of major athletic teams. And what about cosmetic edits that change someone’s physical appearance, or, say, edits that parents might order for their children to prevent them from becoming gay? Some of these cliché science fiction scenarios may prove impossible, but some won’t. And the tools to realize them are already here.
- The latest on rewriting genomes, humans’ included, Tabitha Powledge, Genetic Literacy Project
- Cure for HIV? New gene-editing technique shows promise, Kenrick Vezina, Genetic Literacy Project