Under what circumstances might we permit germline gene editing? The report proposes the following regulatory guidelines. Gene editing of embryos, sperm and egg cells might be permissible, it argues, if:1) There are no other "reasonable alternatives"—i.e., the disease or condition cannot be otherwise treated or prevented reasonably.Because germline genome edits would be heritable, their effects could be multigenerational. As a result, both the potential benefits and the potential harms could be multiplied. In addition, the notion of intentional germline genetic alteration has occasioned significant debate about the wisdom and appropriateness of this form of human intervention, and speculation about possible cultural effects of the technology … these include concerns about diminishing the dignity of humans and respect for their variety; failing to appreciate the importance of the natural world; and a lack of humility about our wisdom and powers of control when altering that world or the people within it.
2) The gene(s) being altered result in "a serious disease or condition";
3) The genes have been "convincingly demonstrated to cause or to strongly predispose to that disease or condition."
2. Government bodies should encourage public discussion and policy debate regarding governance of somatic human genome editing for purposes other than treatment or prevention of disease or disability."So what of the woman with the BRCA-1 mutation? Under the proposed guidelines, a genetic intervention on her eggs would not be easy to justify.To justify genetically editing the mutant BRCA-1 gene from her eggs or embryos, she would have to prove (1) that the disease caused by the mutation (breast cancer) involved extraordinary suffering (2) that there were no other medical alternatives available (3) that the link between the gene and the disease was absolute.In the case of BRCA-1, there can be little doubt about the extraordinary suffering caused by the disease. But the second and third clauses—the absence of a justifiable alternative, and the link between the gene and the disease—are much more nebulous. She could, in principle, use prenatal genetic diagnosis (PGD) to test her eggs or her embryos, and thereby selectively conceive a child lacking the BRCA-1 mutation.Further, current preventative therapies for breast cancer, such as a dual mastectomy or hormonal treatment, do exist (though they are clearly invasive, disfiguring and toxic). And while the lifetime risk of cancer for a woman carrying a BRCA-1 mutation may reach 60 percent, it is hard to predict which woman will be diagnosed with cancer.This pattern, I fear, will be representative of many human diseases, and will interpose some of the most difficult questions for the future of gene editing applications. Most human diseases are not influenced or controlled by single gene variants, and yet some gene variants are strongly linked to the disease. The link between the gene mutation and the disease may not be absolute or predictable, yet the presence of the mutation increases risk substantially. And while current therapies exist for some of these diseases, they are toxic, marginally effective and unpredictable. The report attempts to draw strict boundaries against genetically intervening on such illnesses. But future debates on gene editing in embryos, sperm and eggs will inevitably return to these contentious boundaries—and to personal conundrums faced by this woman with the BRCA-1 gene mutation.Portions of the above were excerpted from THE GENE: An Intimate History (Scribner 2016).Update 2/26/17: an earlier version of this story misrepresented the risks of inheriting a mutated gene. The figures have since been corrected.