Engineering a Cure: Constructing a NonViral Prime Editor for LGMDR1 - Limb Girdle Muscular Dystrophy

This preprint presents a research proposal for a non-viral prime editing therapeutic strategy targeting Limb-girdle muscular dystrophy recessive 1. LGMDR1 is a severely debilitating neuromuscular disorder caused by variations in the CAPN3 gene. Traditional adeno-associated virus gene therapies have struggled with severe safety issues, including fatal hepatotoxicity from systemic high-dose delivery and the threat of ectopic cardiac protease expression. To circumvent these risks, this project focuses on repairing the patient's endogenous mutated CAPN3 sequence directly within the chromosomal DNA.

The research specifically targets the c.2338G>C and c.2051-1G>T founder mutations, which account for up to 89 percent of LGMDR1 cases within the highly endogamous Indian Agarwal community. By utilizing Prime Editing, the researchers propose a method to safely correct these complex transversions and splice-site substitutions without causing double-strand DNA breaks. This editing approach is technologically superior to standard cytosine base editors, which strictly catalyze C-to-T transitions and cannot perform the necessary direct C-to-G transversion required for this mutation.

To deliver these large ribonucleoproteins and mRNA constructs, the project employs Transferrin-targeted Lipid Nanoparticles. These nanoparticles bypass the strict size limits and immune complications of viral vectors. By conjugating the exterior shell with specific biological ligands that bind to Transferrin receptors, the nanoparticles hijack the body's natural iron-transport pathways to actively target dystrophic skeletal muscle. This targeted mechanism avoids the liver sink entirely, allowing for safe, iterative outpatient re-dosing while ensuring the restored calpain-3 enzyme remains under physiological control.

Keywords: LGMDR1, CAPN3, Prime Editing, Lipid Nanoparticles, Agarwal Community, Gene Therapy, Transferrin Receptors, Non-Viral Delivery