A rescue fanconi anemia humanized mouse model with endogenous FA mutation and high human hematopoietic stem cell...

Autologous transplantation of ex vivo gene-modified/corrected hematopoietic stem cells (HSCs) offers a definitive therapeutic approach to restore hematopoiesis in Fanconi anemia (FA) patients. However, this approach not only requires ex vivo treatment of patient HSCs in specialized facilities but also inevitably results in a loss of fragile and limited patient HSCs. In vivo correction of HSCs directly in the patient can overcome these limitations. To develop such in vivo gene therapy (GT) strategies, an appropriate in vivo model with sufficient target human HSCs carrying the disease-associated mutation is crucial. However, due to the proliferative defect imposed on FA-mutant cells, it is difficult to establish a humanized mouse model with a high engraftment of mutant HSCs. Here, we report a humanized mouse model of FA that results in high chimerism with FA-mutant human HSCs. We demonstrate successful engraftment, uncompromised proliferation, and long-term persistence of the FA-mutant HSCs facilitated by the full-length FANCA expression introduced via a lentiviral vector. This model resolves the lack of an in vivo FA disease model with human HSCs and is a promising platform for testing in vivo gene editing strategies targeting human cells.