The birth of gene-edited babies in China last year drew questions and concerns about the long-term safety and ethics of the procedure
- 8 Jan 2019 at 04:00
- WRITER: ARUSA PISUTHIPAN
Twin girls Lulu and Nana are no ordinary children. Claimed as the world's first gene-edited babies, they quickly came under the global spotlight from the moment they came into this world. Now they are being received with great interest and curiosity among not just doctors and scientists but also many people around the world. Even the World Health Organisation (WHO) had to set up a special panel to look at the technique through which the twins were conceived.
"It cannot just be done without clear guidelines," said the head of the United Nations health agency, Tedros Adhanom Ghebreyesus, in Geneva late last year.
The birth of Lulu and Nana made international headlines last November after Chinese scientist He Jiankui, an associate professor at the Southern University of Science and Technology in Shenzhen, announced through an online video that he had created the world's first genetically-edited babies whose DNA is resistant to HIV infection. The technique that he used is called Crispr, which is an editing process to alter a gene in human embryos that is then then implanted back in the womb of a woman. The outcome was Lulu and Nana who were reportedly born healthy.
In the Crispr technique, the Chinese scientist disabled a gene called CCR5. In normal circumstances, CCR5 studs the surface of white blood cells where it acts as a receptor to signalling protein or chemokines. In the case of HIV, which targets white blood cells, the virus uses CCR5 to latch onto them and breach the membrane of white blood cells. So basically, disabling CCR5 means turning off an HIV receptor.
Although this sounds like a miracle prevention in the world of future healthcare where people would no longer be susceptible to being infected with HIV, the case of Lulu and Nana immediately provoked international outcry. Some scientists reportedly said people with disabled CCR5 would be more prone to West Nile virus and Japanese encephalitis and that there are actually simpler and safer ways to prevent an HIV infection than altering the gene. On an ethical side, some worry that this would be the first step towards using the gene-editing approach to create humans with desired intelligence, beauty and ability. The biggest ethical concerns for now, as reported by The New York Times, are with scientists enticing couples who do not realise the risks to babies that might result from the experiments.
Following He's online video, China suspended the work, saying his conduct appeared to be unethical and in violation of Chinese law. A month later, China's Ministry of Education asked universities to inspect all research work on gene editing and submit a report to the government by year end showing the work doesn't breach ethical boundaries.
Thailand's renowned geneticist and expert in molecular medicine Asst Prof Dr Objoon Trachoo said although technically speaking, editing a gene so as to make a person resistant to HIV can be done easily, ethically speaking the issue still remains in question.
"Every medical practitioner shares one similar goal, and that is to save human beings," said Dr Objoon. "But now we have a big ethical issue to take into consideration. How can we know the consequences gene editing will have on babies in the next 10 years, for example? Is it going to affect other genes in the body? These questions remain to be proven and clarified."
Gynaecologist and maternal and foetal medicine specialist Assoc Prof Dr Boonsri Chanrachakul echoed similar concerns.
"Fairly speaking, it is like giving the babies a vaccine against HIV. It doesn't make them smarter or prettier. That's why some claim this is just a preventative approach again an illness."
"Others, on the other hand, say this is unethical," he added. "People can be overwhelmed by greed. They could say that if we can remove the gene that could potentially cause hereditary breast cancer, why not going a little further and alter genes to make them taller, better-looking, smarter or to make them a talented athlete or a musician. They will never have enough."
While the controversy around the gene-editing technique is still being debated, many scientists and medical specialists in Thailand see a bright future in genetics. According to Dr Objoon, genetic science as currently being practised in the country mainly covers three areas: diagnosis, treatment and prevention.
"Diagnosis is when a patient falls sick with a disease of an unknown cause and we try to figure out the contributing factor behind the sickness. We found out that many diseases have genetics to blame such as seizure, visual impairment, hearing disability, heart diseases and cancer. When we can pinpoint that their illnesses are genetic, we can help take better care of the patients to prevent the diseases from deteriorating," explained Dr Objoon.
In terms of treatments, think inherited breast cancer. When the malignancy attacks the right breast, for instance, doctors can help save the left one before the cancer spreads while also caring for the affected areas. Or think Ramathibodi Hospital's gene therapy technique to help thalassaemia patients where a functional human beta haemoglobin gene is inserted into a patient's own stem cells to provide a lifelong treatment for his or her blood disorder.
Prevention is the largest piece of the pie here. Known as carrier screening, the gene-level preventive mode has been practised in Thailand during the past several years.
In a nutshell, carrier screening or carrier testing is a type of genetic testing to help determine if a person is a carrier of certain hereditary diseases. Carrier screening is usually recommended for couples who are planning to have kids to find out the risks of genetic disorders that they could pass onto their soon-to-be-born child.
"In the past, it wasn't until a baby was born that we realised he or she would fell prey to a disease," said Dr Boonsri. "Now that we have carrier screening technology, a couple can get screened prior to pregnancy if they carry genes that could pass diseases to their little ones. If they do and the diseases are not severe, then we can discuss if they want to try having a baby on their own with how much percent chance there is of the baby getting the disease. If it's serious or life-threatening illnesses, perhaps they would want to consider in vitro fertilisation."
Such a gene-level medical advancement, added Dr Objoon, is classified as precision medicine, which covers not only obstetrics and gynaecology but also other medical specialities.
"Carrier screening is not designed only for couples who plan to have babies," he commented. "Many other diseases such as heart diseases, cancer and sudden unexpected death syndrome are genetic. If we are able to find out if a person carries such genes, we will then be able to prevent those diseases from manifesting."
Sounds like a test that only the wealthy can afford. In a sense, yes. But if the screening can be made more widely available, there are high chances that the cost would get relatively lower. "Take prenatal gene screening for Down syndrome, for example," said Dr Boonsri. "Thailand implemented NIPT [Non-invasive prenatal testing] for Down syndrome for the first time in 2012. Back then, it cost over 33,000 baht at private hospitals. People rejected it, saying it was way too expensive. Now people are more aware of the importance of the test and more people opt for it. As of now, you can get NIPT at around 8,000 baht."
So public awareness is a priority. If the significance of carrier screening is widely understood, people would then realise it is one way to prevent certain diseases that could in turn help cut the healthcare burden not just on the household level but also on the national scale.
"Thailand sort of has this type of attitude -- we do not want to bring diseases home," said Dr Objoon. "Half of the country's population are thalassaemia carriers and now we still see women giving birth to babies with thalassaemia. Why didn't they get screened before getting pregnant? This is a huge barrier. And we are not even talking about prices [of the screening] here. In terms of awareness alone, we already lose."
As for gene editing, the geneticist firmly believes further development and study is most required at this point. In his opinion, creating a genetically modified baby should not be carried out unless it is tested and proven that it would have no adverse and long-term consequences on human beings. "We need more studies in humans if gene editing is likely to lead to other complications."
A proper criteria, advised Dr Boonsri, should also be issued to identify which genes can be edited and which cannot.
"At this point, personally I only agree with genetic screening. As for editing, only when we can be assured it would not have colossal negative effects on the genetically-modified person themselves as well as others, then we could give it a go."