The genetic selection technique carried out presents ethical and technical difficulties, so other ethically acceptable alternatives should be sought.
For the first time in Spain, a girl with sickle cell disease has been successfully treated by transplanting cells from her designer baby sister’s umbilical cord and bone marrow. The baby was conceived by in vitro fertilization after being genetically selected from among several embryos generated by the same procedure. Those in charge of treating the 11-year-old girl have been the Hospital de la Santa Creu i Sant Pau in Barcelona and the Fundació Puigvert. Both describe this fact as a “success case” of Spanish medicine.
The disease in question, of genetic origin, is a form of severe anemia that can cause multiple complications such as pain, mobility problems and a high risk of infections. Life expectancy with this disease is around 30 or 40 years.
According to the director of the Hematopoietic Transplant Unit of the Sant Pau Pediatric Service, Isabel Badell, the only possible treatment was a transplant of hematopoietic cells from a donor. In addition, it had to be immunologically compatible with the patient and chromosomally normal.
After hearing this, the parents considered fathering a new child with assisted reproduction using Preimplantation Genetic Diagnosis (PGD). This technique consists of analyzing the embryos formed, discarding those with unwanted characteristics, and keeping the rest for implantation.
Thus, after selecting an embryo not affected by the disease and immunologically compatible with the sick sister, it was implanted in the mother’s uterus for gestation. The idea was that the baby would be born free of the disease and, furthermore, that samples of umbilical cord blood and bone marrow could be taken to transplant them to the eldest daughter and cure her.
They chose a compatible embryo
For this, it was necessary for the mother to undergo three ovarian stimulation treatments. From which numerous oocytes were obtained that were genetically analyzed after being fertilized with the father’s sperm to choose one, healthy and compatible, and discard the rest. The baby, named Sokna, was born in September 2019.
After her birth, blood was extracted from the umbilical cord, but as it was insufficient, bone marrow samples were also taken from the donor sister when she was one year old. The transplant was performed in April 2022.
Are there any bioethical drawbacks?
This practice has been presented to the public opinion as a breakthrough in curing various diseases, including Fanconi anemia, sickle cell anemia, β-thalassemia major, Hurler syndrome, severe immunodeficiencies, leukemias, lymphomas and bone marrow aplasias.
Obtaining a sibling who has a histocompatibility profile identical to that of the patient increases the chances of cure and constitutes a powerful reason for many parents to encourage themselves to have a designer baby that makes it possible.
Since the birth of the first designer baby in the USA, Adam Nash, in the year 2000, after selecting an embryo through preimplantation genetic diagnosis prior to in vitro fertilization, there have been multiple similar attempts, with limited success.
The theoretical statistical probability of obtaining a healthy embryo in other cases, such as that of the Nash brothers, is 3%. In other words, 33 embryos were needed to obtain 1 that would result in a successful pregnancy. In addition, the process lasted four and a half years, including the IVF processes, preimplantation diagnosis and pregnancy. The average cost per cycle was around $20,000 and most importantly, numerous embryos were sacrificed so that only one would be useful to Molly Nash.
The efficacy data offered by the Chicago Institute of Reproductive Genetics in 2005 were even more dramatic. The results of their experiences, together with those of other centers in Australia, Belgium, Turkey and the United States, showed that of 1,130 embryos obtained, only 13 children were born, so their efficiency would be only 1.15%.
Usually, these data do not transcend public opinion, which is informed of the enormous success that the cure of a hitherto incurable disease has entailed. And thanks to the generous donation of hematopoietic material from the umbilical cord or medullary cord by his sibling. And also to the extraordinary progress of the medical sciences that make possible what yesterday seemed impossible.
Some of the “extra” embryos may or may not have been frozen. Some would be sick, some would have abnormalities, and some would simply not be useful anymore.
It is the hidden face of designer babies, who have been euphemistically called “donor children”, “savior siblings”, “beloved children” or “children born by in vitro fertilization with therapeutic intentions.”
A good social acceptance of these practices, carried out for curative purposes, can be verified, as shown by a survey carried out by the BBVA Foundation in 2008, in which the people surveyed approved the use of these techniques for the described purpose. On the other hand, they did not approve its use for sex selection.
It seems necessary to offer the public opinion truthful and unbiased information about what obtaining designer babies entails, so that they can form an opinion based on the evidence of what these techniques entail.
Alternatives to “designer babies”
Today it is possible to carry out a regenerative therapy of blood cells, starting from the stem cells contained in the umbilical cord (UC), as has been known for more than 30 years.
The biggest drawback of using these cells is the limited availability of samples compatible with the patients who need them. This inconvenience can be reduced by expanding the number of public umbilical cord banks. In them there are already hundreds of thousands of units for transplants around the world and they are available to everyone who may need them.
The generalization of the conservation of UC cells in public banks can facilitate obtaining compatible stem cells for all required cases. This would make resorting to the complex, expensive, and ethically conflicting procedure for producing designer babies unnecessary.
The use of assisted reproductive techniques to obtain multiple embryos in order to genetically select one that is useful for treating a sick sibling presents enormous ethical and technical difficulties.
In addition, the designer baby would be subjected to “forced” donation processes, in order to obtain more hematopoietic cells from his bone marrow, with the risk and discomfort that this may cause him. As we have mentioned, the process is slow and years are needed to achieve a successful completion of the transplant.
Therefore, the use of umbilical cord cells from public banks could achieve a sufficient therapeutic arsenal to treat cases that require them.
Other gene editing techniques also open up a promising horizon. These are iPS cells, which are adult cells from the patient that have been reprogrammed and genetically edited to correct the abnormality that causes the disease. These cells can be cultured and reintroduced into the patient himself, thus eliminating the risk of incompatibility.
In a study published in 2009, it was proposed to convert cells obtained for prenatal diagnosis from a sick patient into iPS cells for subsequent treatment in perinatal periods.
Early treatment has the advantage of requiring much fewer cells than adult treatment, and it may also prevent organ damage in diseases where pathology may begin during gestation or at an early age.
In conclusion, the possibilities offered by both the use of umbilical cord cells from public banks and the therapies with iPS cells are promising and present less ethical difficulties than obtaining designer babies.
Julio Tudela and Cristina Castillo
Bioethics Observatory – Institute of Life Sciences
Catholic University of Valencia