NHEJ-Mediated Gene Editing: An Efficient Approach to Correct Mutations in Hematopoietic Stem and Progenitor Cells from Patients with Fanconi Anemia

Non-homologous end-joining (NHEJ) is the preferred mechanism used by hematopoietic stem cells (HSCs) to repair double-strand breaks, and is particularly increased in cells deficient in the Fanconi anemia (FA) pathway. Here we describe for the first time the possibility to correct mutations in FA genes by generating compensatory indels that restore their coding frame. The efficacy of the strategy was first verified in FA lymphoblastic cell lines and then in primary FA CD34 cells, which acquired proliferative advantage and correction of their characteristic FAcell phenotype. Importantly, in contrast to homologous directed repair (HDR), the efficacy of NHEJ to edit primitive human HSCs was comparable to that observed in more mature progenitor cells, indicating that NHEJ-editing approaches should constitute a good approach for the editing of long-term repopulating HSCs and consequently for the treatment of FA and other monogenic hematopoietic diseases.