Earlier this month, scientists at Oregon Health Sciences University announced that they had successfully edited the DNA of a human embryo in order to remove the cause of a relatively common but extremely dangerous genetic disease.
The disease in question, hypertrophic cardiomyopathy, results in the abnormal thickening of the tissue in the heart. Caused by a mutation in the MYBPC3 gene, hypertrophic cardiomyopathy affects an estimated 1 in 500 people worldwide. Most of those afflicted show no symptoms until their heart unexpectedly stops. There is no way to prevent or cure hypertrophic cardiomyopathy, and it generally remains undetected in those carrying the mutant gene until they suddenly drop dead.
Using a tool called CRISPR (or Clustered Regularly Interspaced Short Palindromic Repeats, a type of molecular scissors that genetic engineers can use to selectively cut out and replace genes), the Portland-based research team was able to take embryos carrying the mutant MYBPC3 gene and correct the genetic defect. Had the embryos been implanted and allowed to develop to full term, the resulting children would have been cured of hypertrophic cardiomyopathy. More importantly, the cure would be permanent and would be transmissible. The researchers changed the very DNA of the embryos themselves, a process known as germ-line modification. Modifying the germ-line allows corrected or edited genes to passed on to subsequent generations of children.
This is not the first time that researchers have used CRISPR or similar tools to correct genetic defects in human embryos. In 2015, for example, a team at Sun Yat-sen University in Guangzhou, China, used a similar technique to selectively edit a gene called HBB, which encodes the human β-globin protein. Mutations in HBB gene are responsible for a disease known as β-thalassaemia. Individuals with β-thalassemia suffer from severe anemia, poor growth, and skeletal abnormalities. Left untreated, the disease eventually leads to death. Treatment requires frequent and lifelong blood transfusions, which causes a number of complications including iron overload (which can damage internal organs), splenomegaly requiring surgical removal of the spleen, and heart failure.
Unlike the more recent study, however, the Chinese scientists were only able to modify some of the cells in the embryo. Moreover, there were additional and unintended changes to the germ-line DNA, suggesting that the technique used by the those researchers was potentially unsafe. What makes the American study so exciting is it is the first time that researchers were able to modify embryos safely, efficiently, and precisely, making the prospect of CRISPR-based treatments for genetic disorders more science fact than science fiction.
Despite its great promise, this research is not without its critics. Although the two studies mentioned, and others like them, focus on the use of CRISPR to cure deadly genetic disorders, opponents of germ-line modification have raised concerns about the potential use for non-medical reasons. For instance, Marcy Darnovsky, Executive Director of the Center for Genetics and Society, publicly worries that this technology will soon lead to “designer babies”; fertility clinics in the US and elsewhere will be able to offer wealthy parents the option of engineering their children for particularly desirable traits such as athletic prowess, artistic talent, or high intelligence.
Such criticisms are not nothing new. When it first became possible to genetically modify organisms in the 1970’s, concern citizens worried that these scientific tools could be used to create new and deadly strains of anthrax, influenza, and smallpox (a fear capitalized on by Michael Creighton in his book The Andromeda Strain). So great was the public’s concern that, in February 1975, a group of 140 molecular biologists met at the Asilomar Conference Center in Monterey, California, to discuss ethical issues surrounding the use of recombinant DNA technology. Similar concerns and public debates have occurred following other scientific advances, including the development of artificial reproductive technologies like in vitro fertilization (IVF) and the sequencing of the human genome. Despite what critics think, even morally-problematic studies like those using embryonic stem cells or germ-line modification proceeds in a very controlled and thoughtful way.
Following publication of the Chinese study, CRISPR co-discoverer Jennifer Doudna organized a meeting of 18 renowned researchers, ethicists, theologians, and others to discuss the use of this technology for human germ-line modification. In a subsequent article entitled A Prudent Path Forward for Genomic Engineering and Germline Gene Modification, they called a moratorium on the use of CRISPR clinically until there was “broad societal consensus” about the use of this technology to treat severe and life-threatening diseases. However, they noted – as have many researchers and ethicists before and since – that concerns about designer babies are overblown. Unlike genetic disorders like hypertrophic cardiomyopathy and β-thalassaemia, traits like height, intelligence, and artistic ability are influenced by multiple genes. We don’t even understand how these genes interact to create musical aptitude or athletic prowess. We certainly don’t have the ability to selectively design the next Mozart or Michael Jordan, and we shouldn’t prevent research that may lead to new life-saving medical treatments out of an irrational fear of breeding a generation of uber-Mensch.
The fundamental concern that is commonly raised around new medical advances and scientific technologies like CRISPR is this: Should scientists play God? In fact, a recent Time/CNN poll found that a substantial majority (58%) of Americans believed that altering human genes is “against the will of God.” But this is the wrong question to ask. There is nothing inherently immoral with CRISPR. It is a tool and as such is morally neutral, like all tools. A gun can be used to kill or it can be used to defend. A chainsaw can be used to build or used to destroy. Likewise, CRISPR can be used to treat disease or to create designer babies. It is all in the intent. So the question is not about playing God, but playing a wise and benevolent God. There is nothing wrong with using our scientific knowledge and technical know how to alleviate human suffering, so long we do so prudently and thoughtfully.
[This blog entry was originally presented as an oral commentary on Northeast Public Radio on August 10, 2017, and is available on the WAMC website.]