Social and ethical issues arise beyond potential for preventing rare complex diseases
Sophisticated prenatal techniques, not yet in clinical practice, offer the potential to prevent a cruel multi-system genetic disease passing from mother to child long before birth.
But these emerging tools raise important questions: might there be unintended, even irreversible risks to the resulting child–or even that child’s future descendants? Are there potential risks to the mother’s health? What about other potential consequences if its use is broadened to include indications beyond strict disease prevention, such as adapting the tools into conception aids for older women?
The tools in question, mitochondrial replacement techniques (MRTs), aim to prevent mother-to-child transmission of mitochondrial DNA disease –a complex set of rare disorders caused by defective DNA within the mitochondria, the tiny energy-producing structures existing outside the nucleus of cells. Such disease may present at any age or level of severity, attacking a combination of organs and systems, often fatally. There are no current cures or approved therapies for any of these disorders, which clinicians manage by treating the diverse symptoms that may progressively affect each patient.
Earlier this month, an expert panel of national experts formed by the Institute of Medicine at the request of the U.S. Food and Drug Administration (FDA) recommended that research into MRTs should proceed under carefully proscribed guidelines.
Three members of that panel co-authored a Perspective article in today’s New England Journal of Medicine on MRT’s implications for clinicians. The article begins, “Mitochondrial DNA (mtDNA) disease may be the poster child for highly targeted, ‘personalized’ medicine.”
“Even though MRTs would not confer health benefits on patients who already have mitochondrial DNA diseases, many patients with a known risk for transmitting such a disease to their offspring are highly motivated to prevent that from occurring,” said Marni J. Falk, M.D., director of the Mitochondrial-Genetics Clinic at The Children’s Hospital of Philadelphia and first author of the article. “That motivation is clear when we counsel patients and families affected by mtDNA disease, and recent patient surveys have reinforced that preventing disease transmission is a prevailing concern in this population.”
Falk’s co-authors are Jeffrey Kahn, Ph.D., M.P.H., of the Johns Hopkins Berman Institute of Bioethics, and Alan Decherney, M.D., an obstetrician-gynecologist and reproductive endocrinologist at the National Institute of Child Health and Human Development.
Kahn chaired the Institute of Medicine expert panel.
Because the expert panel stated that the child’s safety was paramount, it recommended that MRTs should initially be studied only in male embryos, since males do not transmit mitochondrial DNA to their children. The panel further argued that the FDA should make clear policy and that professional societies should issue practice recommendations to limit future MRT usage to appropriate patients.
The authors repeat the panel’s stipulation that children conceived after MRT should be monitored long-term, “probably well into adulthood,” much longer than is done after in vitro fertilization with pre-implantation diagnosis for diseases based in nuclear DNA.
Finally, because MRTs require mixing mitochondrial DNA from a female donor with DNA from the nucleus of the mother and father, the authors note that researchers should investigate unanticipated health problems and possibly questions about identity, before regulatory approval or clinical use can occur for the techniques.
The Latest on: Mitochondrial DNA replacement
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The Latest on: Mitochondrial DNA replacement
- How mothers transfer the DNA inside their mitochondria to their babieson October 4, 2019 at 7:36 am
... replacement, can result in low levels of heteroplasmy, which is shown to be more frequent in patient populations than was considered the case till now. This type of treatment is designed to stop ...
- CNIC scientists discover a new mechanism for the transfer of maternal genetic materialon October 4, 2019 at 5:38 am
... "will likewise help us to devise ways to prevent different types of mitochondrial DNA co-occurring in the same cell as an unwanted result of medical interventions; this phenomenon, known as ...
- Scientists discover a new mechanism for the transfer of maternal genetic materialon October 4, 2019 at 2:07 am
... "will likewise help us to devise ways to prevent different types of mitochondrial DNA co-occurring in the same cell as an unwanted result of medical interventions. This phenomenon, known as ...
- 'Matching' DNA could make for healthier 3-parent babies: studyon September 21, 2019 at 5:00 pm
using a technique called mitochondrial replacement therapy. The nuclear DNA is taken from their own egg, and placed with the father's sperm into a different egg, its nucleus removed, from a donor with ...
- Mitochondrial Genetic Alterations: A Clinical Trial of a Standardized Research E-cigaretteon August 22, 2019 at 6:05 am
This study will focus on the effects of e-cigarette use on mitochondrial DNA (mtDNA) in the lung and nasal tract ... or receive nicotine replacement therapy (NRT). A follow-up bronchial and nasal ...
- Ancient DNA reveals new twists in Neanderthal migrationon June 27, 2019 at 2:42 am
They then extracted both mitochondrial DNA, which is a genetic fraction passed from mother ... And since the pair is similar in age to the Altai Neanderthal, the population replacement may have even ...
- OHSU scientist reacts to continued Congressional ban on genetically altered embryoson June 6, 2019 at 1:46 pm
“We know how much mitochondrial replacement therapy means to families who have devastating mitochondrial diseases,” he said. “We have worked for years to improve scientific understanding of ...
- In support of mitochondrial replacement therapyon June 3, 2019 at 10:36 am
Novel Techniques for the Prevention of Mitochondrial DNA Disorders: An Ethical Review (Nuffield Council ... National Academies of Sciences, Engineering, and Medicine. Mitochondrial Replacement ...
- U.S. researcher says he’s ready to start four pregnancies with ‘three-parent’ embryoson April 17, 2019 at 5:00 pm
Mutations in mitochondrial DNA can cause serious genetic diseases ... There, he transferred an embryo created with mitochondrial replacement therapy into a woman who’s a carrier of Leigh syndrome. She ...
- Patient advocates and scientists launch push to lift ban on ‘three-parent IVF’on April 15, 2019 at 5:00 pm
These diseases are inherited from the mother’s DNA, so mitochondrial replacement therapy involves taking the nucleus of the mother’s egg and swapping it into a donor egg that has had its nucleus ...
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