As a model system, we applied the MAGE‐CRISPR to edit a mutated gene in stem cells derived from a patient with Rett syndrome, a rare genetic disorder caused by de novo mutations in the mutated X‐linked methyl CpG‐binding protein 2 (MeCP2) gene (Figure S1, Supporting Information). The gene discussed is MECP2; the disease is atypical Rett syndrome.