Changing Genes
Wednesday, August 9th, 2017August 9, 2017
On August 2, a team of scientists from the United States, China, and South Korea announced that they had successfully corrected a harmful disease-causing genetic defect in human embryos. In a groundbreaking experiment, the scientists used a technique called CRISPR-Cas9 (see explanation below) to “edit” a faulty gene in dozens of human embryos. The faulty gene causes a common heart condition that can lead to sudden death later in life. Most of the altered embryos became completely healthy as a result of the procedure. If the embryos were allowed to develop into babies, they would not only be free of the harmful genetic condition, but they would also not pass the disease to any of their descendants. The results of the experiment were published in the online edition of the journal Nature.
None of the embryos in the experiment was allowed to grow and develop. However, the scientists conducted the experiment as part of research they hope will ultimately help families that suffer from inherited diseases. Such inherited disorders in humans include cystic fibrosis, hemophilia, muscular dystrophy, sickle cell anemia, and Tay-Sachs disease. Many scientists believe that such diseases can eventually be cured or even eliminated through genetic engineering—the term applied to techniques that alter the genes or combination of genes in an organism, including human beings.
CRISPR (Clustered Regularly Interspaced Short Palindromic Repeat) refers to a genetic engineering technique that was developed in 2012. It is derived from a process that scientists first observed occurring naturally in bacteria in 1987. The technique uses a protein designated Cas9, which is obtained from bacteria, to break DNA at highly specific locations. Scientists can manipulate this CRISPR-Cas9 process to delete, alter, or replace a gene with great accuracy.
Despite the potential benefits of this technology, experts in scientific ethics are debating whether CRISPR-Cas9 and other advanced gene-editing techniques should be used to alter human embryos. They worry that the techniques could be abused to create genetically modified “designer babies” with made-to-order characteristics. There are also fears that any mistakes in the gene-editing process could inadvertently cause other unknown health problems or even new diseases. These new diseases could then be passed down through families.
Most countries have regulations that limit or prohibit experiments with gene-editing techniques involving humans. The U.S. National Institutes of Health (NIH) prohibit laboratories that receive federal funds from experimenting with human embryos. Such experiments can be done in privately funded laboratories, however, as this experiment was. In addition, the U.S. Food and Drug Administration (FDA) is prohibited from evaluating any treatments that involve genetically modified human embryos. However, government regulations in other countries, including China and the United Kingdom, have recently permitted limited experiments involving human embryos.