Therapeutic strategy for spinal muscular atrophy by combining gene supplementation and genome editing

Defect in the SMN1 gene causes spinal muscular atrophy (SMA), which shows loss of motor nerve cells, muscle weakness and atrophy. While current treatment strategies, including small molecules or viral vectors, have been reported to improve motor function and survival, an ultimate and long-term treatment to correct SMA endogenous mutations and improve its phenotypes is still highly challenging. We have previously developed a CRISPR-Cas9 based homology-independent targeted integration (HITI) strategy, which allowed for unidirectional DNA knock-in in both dividing and non-dividing cells in vivo . Here, we demonstrated its utility by correcting a SMA mutation in mice, and when combined with Smn1 cDNA supplementation show SMA long-term therapeutic benefits in mice. Our observations may provide new avenues for long term and efficient treatment of inherited diseases.