Quirks & Quarks

1st ever gene-edited human embryo raises ethical concerns

Researchers say none of the embryos were allowed to develop for more than a few days, and that none were implanted into a womb.
The first sign of successful in vitro fertilization, after co-injection of a gene-correcting enzyme and sperm from a donor with a genetic mutation known to cause hypertrophic cardiomyopathy. (Oregon Health & Science University)

First human case

This year, scientists say they successfully corrected an inherited gene mutation in a human embryo responsible for a type of heart disease. While the procedure has great potential, it also raised questions about safety and ethics of manipulating the human genome.

Dr. Shoukhrat Mitalipov, principal investigator at the Center for Embryonic Cell an Gene Therapy of Oregon Health & Science University, says the procedure can only be done on sperm or eggs that parents pass on to children.

Why edit embryos?

In this case, the idea was to correct a mutation that encodes for heart muscle and leads to hypertrophic cardiomyopathy. Once the child is born, often there's already too much damage to the organs or tissue to correct the mutation and change it back to normal, Mitalipov said.

He said scientists could use a similar approach of using the gene editing tool called CRISPR to recognize and flag the mutant gene in sperm. Once that happens and the egg is about to be fertilized or at that time, the egg's own DNA repair mechanism kicks in to glue back the broken piece and repair any abnormality.

Safety and ethical concerns

Mitalipov acknowledged that off-target effects that they haven't identified are still possible, which is investigators need to perform more safety tests before they attempt clinical trials.

Embryos after co-injection developing into blastocysts, which could someday be used in fertility clinics to help people trying to have children free of genetic disease. (Oregon Health & Science University)

He called concerns about the experiment opening the floodgate to human eugenics and designer babies legitimate ones that need to be regulated.