Details were revealed in the journal “Nature” on gene editing on human embryos conducted for the first time in the United States. The experiment successfully edited DNA to erase a heritable heart condition. The embryos only grew for a few days and were never intended to be implanted to create a pregnancy. The researchers’ ultimate goal is to be able to “correct” disease causing genes in embryos that will develop into babies. The laboratory tool used is a type of “molecular scissors.” The work itself, is a particularly sensitive issue as it involves the germ line, i.e. genes that could be passed on to future generations.
The United States forbids use of federal funds for embryo research. The Food and Drug Administration is prohibited from considering any clinical trials that involve genetic modifications that can be inherited. However, conditions were set by which research should continue by the National Academies of Science, Engineering, and Medicine with regard to human germ editing.
While there are huge ethical and legal issues to be discussed regarding modifications of humans, this type of work is different because it involves “correcting” genes, rather than changing them. These researchers don’t edit or modify anything; their program is targeted at correcting mutant genes. Some bioethicists feel concerns about this work have been overblown. Scientists are nowhere near “the dawn of the era of the designer baby.” Characteristics such as intelligence are influenced by multiple genes and researchers do not understand of how this is inherited much less have the ability to redesign it.
The research involved sperm that carried the gene which causes hypertrophic cardiomyopathy injected into eggs. HCM is a disease of the heart muscles that can cause no symptoms and remain undetected until it causes sudden cardiac death. There is no way to prevent or cure it. At about the time the sperm was injected, researchers snipped out the gene that causes HCM. The result was more successful than expected. As the cells started to divide and multiply, a large number appeared to repair themselves by using the normal, non-mutated copy of the gene from the female genetic material. In addition, researchers noticed there was no other effects to the DNA, a major safety concern of gene-editing research.
It is hoped that one day the technique could be applied to a wide range of genetic diseases, of which more than 10,000 can be traced back to a single gene. Researchers feel there are many advantages to treating an embryo rather than a child or adult. An embryo in its earliest stages involves only a few cells whereas a mature human being has trillions of cells in the body and potentially millions that must be corrected to cure the disease. A drawback is that the technique, even if perfected, could only deal with a small subset of human diseases and the number of people in the world who would benefit would be rather small. The child would have to be conceived through in vitro fertilization and parents would have to know the child has the gene for a disease to get it changed. The correction technology cannot be done in utero.
It is hoped that regulators will provide guidance on what should or should not be allowed. The fear is that this technology would be shifted to unregulated areas and should not be allowed to happen.
How do you feel about this line of research being continued? Could it be a salvation for certain diseases or the beginning of manipulations that will be misused?
What do you think?
Source: Star-Ledger, August 2017, Ariana Eunjung Cha, Washington Post