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. Gene therapy using lentivector has helped people with CGD. Researchers want to know if the 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 receive the base-edited cells after chemotherapy with busulfan. Participants will remain in the hospital until their immunity recovers. Participants will be maintained on sirolimus to prevent an immune response to the new protein expressed by the base-edited cells. Follow-up visits will continue for 15 years.