CRISPR-Cas9 gene repair of hematopoietic stem cells from patients with X-linked chronic granulomatous disease

Targeted gene therapy has been hampered by the inability to correct mutations in stem cells that can reconstitute the immune system after transplant into patients. De Ravin et al . now report that CRISPR, a DNA editing technology, corrected blood stem cells from patients with an immunodeficiency disorder (chronic granulomatous disease) caused by mutations in NOX2. CRISPR-repaired human stem cells engrafted in mice after transplant and differentiated into leukocytes with a functional NOX2 protein for up to 5 months. The authors did not detect off-target treatment effects, suggesting that this gene repair strategy may benefit patients with chronic granulomatous disease or other blood disorders.