What Do We Really Think About Human Germline Genome Editing, and What Does It Mean for Medicine?

Genome editing has captured widespread attention because of its potential therapeutic applications. Early studies with human embryos have established the feasibility of human germline genome editing but raise complex social, ethical, and legal questions. In light of the potential impact of genome editing on the practice of cardiovascular medicine, we surveyed ≈300 attendees at a recent American Heart Association conference to elicit their opinions on somatic and germline genome editing. The results were revealing and highlight the need to broadly engage the public and solicit the opinions of various constituencies before proceeding with clinical germline genome editing. Genome editing with clustered regularly interspaced short palindromic repeats/clustered regularly interspaced short palindromic repeat–associated 9 (CRISPR/Cas9) has proven so effective in vitro and in vivo that human therapeutic applications are already under pursuit. Clinical trials for somatic genome-editing therapies, that is, modification of cells, tissues, and organs in living people, have been announced in the United States and China. The first reports of human germline genome editing (GGE), that is, embryo modification, were published in 2015 and 2016, although those studies used nonviable embryos and relatively crude first-generation CRISPR/Cas9 tools. A more recent report in August 2017 of GGE to correct a disease-causing gene mutation in viable human embryos that, in principle, could have been carried to term and resulted in healthy offspring was widely heralded in the press as a breakthrough and drew considerable attention.1 What was particularly notable about this study was that the correction of the mutation was efficient and specific—unlike the earlier studies, unintended mutations were not observed elsewhere in the genome (off-target effects) in edited embryos, and mosaicism (mutations present in some cells in the embryo but not in …