Ctrl-Alt-inDel: genome editing to reprogram a cell in the clinic.

Genome editing with engineered nucleases (zinc finger, TAL effector, or CRISPR/Cas9-based) enables `write' access to regulatory programs executed by primary human cells. A decade of its clinical development, along with a reduction of conventional gene therapy to medical and commercial practice, has made cell reprogramming via editing a viable clinical modality. Reviewed here are the first examples of this to enter the clinic: ex vivo edited T cells for infectious disease and cancer, and hematopoietic stem/progenitor cells for the hemoglobinopathies. Three ongoing developments will ensure that the range of edited and reprogrammed cells to enter the clinic, and the scope of target indications, will grow markedly in the next five years: our ability to identify disease-relevant targets in noncoding regulatory DNA, which is uniquely suited for editing-based cell program control; recent reduction to clinical practice of in vivo editing; and progress in engineering and manufacture of differentiated cells from pluripotent progenitors.