Proposed treatment to fix genetic diseases raises ethical issues

Excerpted from “Proposed treatment to fix genetic diseases raises ethical issues,” Shots: Health News from NPR. August 14, 2013 -- The federal government is considering whether to allow scientists to take a controversial step: make changes in some of the genetic material in a woman's egg that would be passed down through generations. Mark Sauer of the Columbia University Medical Center, a member of one of two teams of U.S. scientists pursuing the research, calls the effort to prevent infants from getting devastating genetic diseases "noble." Sauer says the groups are hoping "to cure disease and to help women deliver healthy, normal children."

But the research raises a variety of concerns, including worries it could open the door to creating "designer babies." Specifically, the research would create an egg with healthy mitochondrial DNA (mtDNA). Unlike the DNA that most people are familiar with—the 23 pairs of human chromosomes that program most of our body processes—mtDNA is the bit of genetic material inside mitochondria, living structures inside a cell that provide its energy.

Scientists estimate that 1 in every 200 women carries defects in her mtDNA. Between 1 in 2,000 and 1 in 4,000 babies may be born each year with syndromes caused by these genetic glitches; the syndromes range from mild to severe. In many cases, there is no treatment, and the affected child dies early in life. "We have developed a technique that would allow a woman to have a child that is not affected by this disease, and yet the child would be related to her genetically," says Dieter Egli of the New York Stem Cell Foundation.

But this is all still very controversial. First of all, the baby would be born with genes from three different people: from the father, from the woman trying to have a healthy baby, and from the woman who donated the healthy egg. There are even bigger concerns, which start with whether the technique is safe for the resulting infant, and whether by trying to fix one problem, scientists may inadvertently introduce mistakes into the human genetic code. That's why this sort of thing has always been off-limits — even banned in many countries, according to Marcy Darnovsky of the Center for Genetics and Society.

Commentary

CMDA CEO David Stevens, MD, MA (Ethics): “Germline genetic engineering, where a portion of the egg or sperm’s genome replaced, changed or supplemented, is unethical, unnecessary and unsafe. It crosses a bright line in the bioethical sand labeled, ‘That shalt not!’


“It is unethical because it permanently changes the child’s genes and any unforeseen consequences that occur are passed on to every generation that follows. Thus, it violates the ethical principle of autonomy. How does the doctor get informed consent from their grandchild yet to be conceived? Some of the techniques proposed involve destroying human embryos, not just manipulating women’s eggs. For example, some propose discarding female embryos created and only implanting male embryos to avoid the risk of passing on an inheritable defect.

“It is unnecessary. Women who have an identified high risk with a high mutation load, (under 18 percent mutations of mtDNA, there is 95 percent certainty of no risk) already have the option of not having children, adopting, utilizing a donated egg, preimplantation genetic diagnosis and prenatal diagnosis with abortion. Some of these options are unethical because they destroy life, but they are legal. Scientists are trying to justify germline manipulation so that women with this genetic liability might have the option of having a child with their genes. While this ambition is understandable, because there are alternatives, and because there are significant risks to generations of offspring, we should prohibit this option.

“It is unsafe. This type of genetic manipulation is not human cloning but uses similar techniques that have been associated with serious problems when used in animals—large organ syndrome, malformations and miscarriages.

“The ‘hard cases’ have been historically used to justify crossing the ‘bright lines’ in bioethics. We saw this in abortion, but once society agreed that abortion was justified because the mother didn’t want a child because of rape, incest or a genetic defect, it soon became justified for a woman not wanting a child for any reason. In other countries, physician-assisted suicide was justified for patients who had lives ‘not worthy to be lived’ because they were terminally ill and suffering. Now it is allowed for any reason the patient conceives that their life is unworthy to live. It is not unreasonable to predict if society says germ line manipulation is okay to avoid having a child with an imperfect genome that society will soon open the door for germline genetic engineering in the quest for perfect children.”

Resources
Novel techniques for the prevention of mitochondrial DNA disorders
Position Paper on Human Germline Manipulation
CMDA Resources on Reproductive Technology and Health