CRISPR gene editing can modify gene functions and alter DNA sequences. This enables it to correct DNA defects in crops, which helps prevent the spread of disease. It can also be used in humans. For example, in China, scientists edited the genomes of twin girls to give them a natural immunity to a particular type of HIV – an experiment that provoked a storm of criticism. The ethics of that project notwithstanding, gene editing does have many positive applications for human health, and there are several diseases CRISPR technology can cure.
Sickle Cell Disease
Until CRISPR cell line gene editing became a thing, the only possible treatment for a patient afflicted with sickle cell disease was a bone marrow transplant. Sickle cell disease is an inherited disease, and the symptoms arise when both parents have the abnormal HBB gene. CRISPR technology can repair the mutation on the affected gene, so they can produce normal hemoglobin. Another approach is to switch off the mutant gene, which has proven very successful in clinical trials.
Finding a cure for cancer is the Holy Grail and CRISPR is proving useful. Chinese scientists have carried out several clinical trials using CRISPR-Cas9 to modify T cells. A trial using patients suffering from non-small cell lung cancer was very successful. Another trial in the US found gene editing could help patients with advanced cancer and was safe to use. Further research is currently being carried out to test the efficacy of CRISPR technology on blood cancer patients.
Cystic Fibrosis can be caused by several mutations in the CFTR gene. There are some treatments available for CF patients, but their average lifespan is still only 40 years. Researchers have been investigating the possibility of using CRISPR gene editing technology to repair some of the mutations in vitro, so that no further damage occurs. It is hoped that work in this area will lead to viable treatments for patients with cystic fibrosis, including those with the rarest gene mutations.
People with the muscular dystrophy gene mutation suffer from progressive muscle degeneration and treatment options are very limited. Researchers are currently working with CRISPR technology to edit the affected gene whereby sections of mutated protein are removed. Research carried out on mice showed gene editing technology had great potential.
Most therapies don’t work with HIV because the virus inserts DNA in healthy immune cells, where it remains hidden until activated. CRISPR gene editing technology could be used to cut out the viral DNA. It could also be used to add natural resistance, as was done in the Chinese experiment on human embryos. However, many experts believe editing genes in embryos could have unintended side effects.
Huntington’s disease has a strong genetic component, whereby parts of the brain cease working over time, which eventually leads to death. Gene editing in the brain is very tricky and potentially very dangerous, but researchers have been working to hone CRISPR technology so it’s more accurate and, therefore, safer.
Finally, CRISPR technology has proven useful in the fight against COVID-19. Stanford scientists used CRISPR Cas13a to remove the virus’s genetic material before it could enter cells. Preliminary trials on mice were very successful.