Researchers at Beam Therapeutics have developed a redesigned base editor that shows considerable promise in directly repairing the single-base mutation that causes sickle-cell disease (SCD). Many strategies are being pursued to harness genome editing approaches including CRISPR to treat patients with SCD and related hemoglobinopathies. The most advanced method in the clinic involves targeting an upstream regulatory pathway to switch on expression of the fetal hemoglobin gene but does not target the SCD mutation directly.