FDA Explores '3-Person' Embryo Fertilization
Meant to prevent genetic diseases in children, the procedure raises ethical issues
WebMD News Archive
The procedure is aimed at preventing illness caused by defective DNA in a mother's mitochondria, the tiny structures that produce energy to power individual cells.
During reproduction, an embryo inherits nearly all the maternal mitochondria present in the egg. That means any genetic mutations present in the mitochondria will be passed on from mother to child, according to the OHSU website.
About one in every 5,000 American children inherits genetic illnesses from their mother's mitochondrial DNA. These diseases can lead to health problems as far-ranging as blindness, organ failure, epilepsy, cancer and diabetes, the OHSU noted.
The new technique seeks to avoid this by using an egg from a healthy female donor that contains undamaged mitochondria. The nucleus DNA of the prospective mother is implanted into the donated egg, replacing the nucleus DNA of the donor.
The result: a child who inherits the mother's nucleus DNA, which contains most of a person's inherited traits, but the donor's healthy mitochondrial DNA. The child could have the mother's eye color or height, but would not run the risk of inheriting a genetic disease from the mitochondria.
Such genetic tinkering raises concerns among many bioethicists. In a letter to the FDA, the nonprofit Center for Genetics and Society noted that "more than 40 countries, including those with the most highly developed biomedical sectors, have adopted policies on human germ-line modification, and all of these have prohibited it."
"This emerging global policy consensus has been supported by the major international biomedical and bioethical organizations and councils," the letter continued. "We believe that it would be unconscionable for the United States to unilaterally cross this bright technical and policy line that has been observed internationally for decades."
The center's letter also questioned how useful the new procedure would be.
"We sympathize with women who place a high importance on having children genetically related to them. But we note that the number of women who would be candidates for the techniques in question is quite small," the letter stated. "While about one in 5,000 to 10,000 people suffer from mitochondrial diseases, only about 15 percent of mitochondrial disease is caused solely by mitochondrial DNA mutations," the letter said.