Table 1.

List of published studies using CRISPR-Cas9 genome editing^a on human embryos

Year	Authors	Title	Type of modification	Embryos used
2017	Ma et al.	Correction of a pathogenic gene mutation in human embryos	Correction of a mutation that causes hypertrophic cardiomyopathy	Viableb embryos created for the purpose of research (>100 embryos were created) using oocytes and sperm procured specifically for research
2017	Tang et al.	CRISPR/Cas9-mediated gene editing in human zygotes using Cas9 protein	Correction of a mutation in HBB gene causing β-thalassemia and a mutation in G6PD gene related to a common enzyme deficiency	Viable embryos created for the purpose of research using oocytes and sperm from patients undergoing clinical IVF procedures
				Non-viable tripronuclear embryos created in clinical IVF procedures
2017	Fogarty et al.	Genome editing reveals a role for OCT4 in human embryogenesis	Study of the function of the pluripotency transcription factor OCT4 during embryogenesis	Viable surplus embryos created in clinical IVF procedures
2016	Kang et al.	Introducing precise genetic modifications into human 3PN embryos by CRISPR/Cas-mediated genome editing	Introduction of an allele of the gene CCR5 associated with a resistance or slower progression of HIV infections	Non-viable tripronuclear embryos created in clinical IVF procedures
2015	Liang et al.	CRISPR/Cas9-mediated gene editing in human tripronuclear zygotes	Modification of HBB gene, which when mutated causes β-thalassemia	Non-viable tripronuclear embryos created in clinical IVF procedures

^aAnother GE approach called base editing has also been studied in human embryos. For a summary of base editing studies, see Lea and Niakan, 2019.

^bViable embryo can develop into a live birth; non-viable embryos do not have such ability due to various abnormalities.

HIV, human immunodeficiency virus; IVF, in vitro fertilization.