Alpha thalassemia major (ATM) is a genetic condition resulting from inheritance of mutations that delete all four α-globin genes and is often lethal in utero. Fortunately, the advent of fetal blood transfusions allows the survival of infants until birth. After birth, the baby can either be maintained on transfusions or offered a bone marrow transplant. As bone marrow transplants pose inherent risks and matched donors can be difficult to find, there is an unmet need to develop innovative approaches that can offer a definitive cure for ATM.
CRISPR-Cas genome editing holds great promise for the treatment of many genetic diseases. However, no CRISPR gene editing option for treatment of ATM patients has been described. Patients with ATM usually survive the first trimester due to the production of ζ-globin, the embryonic version of α-globin, which is silenced early in development. Thus, reactivating the production of ζ-globin could be a therapeutic strategy in ATM patients to improve survival and avoid bone marrow transplantation.
We aim to study the developmental silencing of ζ-globin and find strategies to reactivate ζ-globin in patients with ATM. We focus on finding feasible gene editing strategies that can provide a cure for ATM patients by upregulating ζ-globin. To do so, we will run an unbiased tiled CRISPR screen across the α-globin cluster to search for genetic elements that regulate ζ-globin expression. HUDEP2 cells, an immortalized cell line derived from CD34+ cord blood that expresses adult α-globin but no ζ-globin, will serve as a model for these experiments. Additionally, we engineered HUDEP2 cells that carry the most common ATM deletion. We will use these ATM model cells to study the effect and efficacy of our gene editing approach.