Site-specific gene correction of a point mutation in human iPS cells derived from an adult patient with sickle cell disease.

Human induced pluripotent stem cells (iPSCs) bearing monogenic mutations have great potential for modeling disease phenotypes, screening candidate drugs, and cell replacement therapy provided the underlying disease-causing mutation can be corrected. Here, we report a homologous recombination-based approach to precisely correct the sickle cell disease (SCD) mutation in patient-derived iPSCs with 2 mutated β-globin alleles (β(s)/β(s)). Using a gene-targeting plasmid containing a loxP-flanked drug-resistant gene cassette to assist selection of rare targeted clones and zinc finger nucleases engineered to specifically stimulate homologous recombination at the β(s) locus, we achieved precise conversion of 1 mutated β(s) to the wild-type β(A) in SCD iPSCs.