Recent Advancements in Ex Vivo CRISPR/Cas9 Gene Editing for Hemoglobinopathies: A Systematic Review of Clinical and Preclinical Progress

Abstract

This systematic review provides an overview of recent developments in ex vivo CRISPR/Cas9 applications to gene editing to address hemoglobinopathies, predominantly sickle cell disease and 1 -thalassemia. The papers published between 2020 and 2025 were evaluated and discussed molecular techniques, such as non-homologous end joining (NHEJ), homology-directed repair (HDR), base editing, and prime editing. BCL11A enhancer editing and fetal hemoglobin reactivation are the most advanced strategies clinically and with current evidence. The other factor leading to these promising outcomes in preclinical research is the possibility of base editing and prime editing to allow a more precise genetic correction, with less risk of causing a double-strand DNA break. Many important challenges still need to be solved, including off-target effects, genetic mosaicism, delivery efficiency, and clonal hematopoiesis after treatment, when mutations occurring in HSCs confer a proliferative advantage to those cells, resulting in malignancies− the risk of genotoxicity due to the high cost and need for special treatment centers. Conclusion: ex vivo CRISPR-based therapy is a powerful new therapeutic option in hemoglobinopathies that we hope to implement clinically, but still, it is hindered by hurdles in long-term safety and in translational considerations of access and cost