Base Editing for Mutation Repair in Hematopoietic Stem & Progenitor Cells for X-Linked Chronic Granulomatous Disease

Background: Chronic granulomatous disease (CGD) is a rare immune disorder caused by a mutation in the CYBB gene. People with CGD have white blood cells that do not work properly and are at greater risk of getting infections. Researchers want to know if gene therapy using the patient's own base-edited stem cells can improve the white cells' functioning and result in fewer CGD-related infections. Objective: To learn if base-edited stem cells will correct the white blood cells in people with CGD. Eligibility: Males aged 18 years and older with X-linked CGD. Design: This is a non-randomized study. Participants with the specific mutation under study will be screened during the initial phase. During the development phase, participants will undergo apheresis to collect stem cells for base-editing correction of the mutation. During the treatment phase, participants will first receive Campath (alemtuzumab) to reduce the risk of an immune response to the new protein expressed by the base-edited cells. This will be followed by conditioning chemotherapy with busulfan and subsequent infusion of the base-edited stem cells. Participants will be maintained on sirolimus to further reduce the risk of an immune response to the new protein expressed by the base-edited cells. Follow-up visits will continue for 15 years.