OHSU genetic research that could eliminate diseases faces clinical obstacles

For the first time, researchers in the USA have safely repaired a disease-causing gene in human embryos, targeting a heart defect best known for killing young athletes - a big step toward one day preventing a list of inherited diseases.

Reflecting the combination of fear and wonder represented by the development, one of the researchers said: "We are finally starting to address disease-causing mutations that impact potentially millions of people" - before highlighting the dangers of taking this breakthrough in technology to its logical conclusion of creating the "perfect" offspring. The researchers concluded that "The efficiency, accuracy and safety of the approach presented suggest that it has potential to be used for the correction of heritable mutations in human embryos by complementing preimplantation genetic diagnosis".

The milestone, revealed in i last week and formally announced tonight, saw scientists demonstrate convincingly for the first time how the defective genes behind hereditary diseases can be corrected in a human embryo. "The application of this technology to clinical practice in the future requires not only additional research, but also social consensus".

As the eggs were fertilised, researchers applied a gene-editing tool, which works by cutting away the defective parts of the gene and allowing the cell to fix itself.

The research on human embryos is strictly regulated and there was no question of implementing those of the study in a woman's uterus to initiate a pregnancy. A patient with this mutation donated his sperm and skin cells for the study.

Led by Shoukhrat Mitalipov of Oregon Health & Science University, the team injected eggs from healthy donors with sperm from a donor with hypertrophic cardiomyopathy, a common condition characterized by irregular heartbeat and heart failure.

Well, that debate is front and centre again now that scientists have figured out a way to "edit out" genetic defects from human embryos, bringing forward a slew of ethical questions.

There were 58 embryos containing the genetic mutation, and the scientists found that the faulty gene was corrected in 42 embryos, making it a success rate of 72%. In the remaining 27.6% embryos, the cellular cut-repairing mechanism introduced some unwanted insertions or deletions near the cut.

Unlike research groups before them - which worked on embryos that were not capable of ever becoming a baby - this study involved the creation of healthy human embryos specifically for research purposes.

The scientists on the call said that while they targeted this particular disease in the experiment, they hope to carry out similar future experiments on other genetic diseases. In short, CRISPR is a gene-editing technique which allows scientists to insert, remove and correct DNA within a cell with pinpoint precision.

The research used blastocysts, structures that form in the womb several days after conception and are used in modern in vitro fertilization (IVF) treatments. It is directed to a specific location in the DNA and performs a cut-and-paste function, not unlike word-processing software. Congress has barred the Food and Drug Administration from considering clinical trials involving germline engineering. The phenomenon of "mosaicism" (simultaneous presence of genes in healthy and defective in embryo) could not be avoided, the researchers of the new study have been able to do. The work was consistent with recommendations issued this year by the National Academy of Sciences and the National Academy of Medicine joint panel on human genome editing. However, the goal is to figure out a way to prevent children from being born with genetic diseases - not create designer babies or super soldiers, despite what the guy wearing a tinfoil hat may tell you.

  • Aubrey Nash