Limb girdle muscular dystrophy type 2A (LGMD2A), caused by mutations in the Calpain 3 (CAPN3) gene, is an incurable autosomal recessive disorder that results in muscle wasting and loss of ambulation.
To test the feasibility of an autologous induced pluripotent stem cell (iPSC)-based therapy for LGMD2A, here the authors applied CRISPR-Cas9-mediated genome editing to iPSCs from three LGMD2A patients to enable correction of mutations in the CAPN3 gene. Using a gene knockin approach, they genome edited iPSCs carrying three different CAPN3 mutations, and they demonstrated the rescue of CAPN3 protein in myotube derivatives in vitro. Transplantation of gene-corrected LGMD2A myogenic progenitors in a novel mouse model combining immunodeficiency and a lack of CAPN3 resulted in muscle engraftment and rescue of the CAPN3 mRNA.
Thus, the researchers provide here proof of concept for the integration of genome editing and iPSC technologies to develop a novel autologous cell therapy for LGMD2A.