Base and Prime editing of DNA as new personalized treatment for Rett disease

Rett syndrome (RTT) is a debilitating neurological disorder caused by mutations in the MECP2 gene. Notably, while loss of MeCP2 function causes RTT, locus duplication causes a severe neurodevelopmental disorder, indicating as MECP2 is a dosage-sensitive gene, with both loss and gain of function causing disease.  Among all pathogenic variations, eight single nucleotide recurrent changes account for ~70% of all identified variations.

At present there is no cure for RTT. Gene therapy, genome and RNA editing strategies provided promising results in mice but are far for being optimized. Here, we propose to develop base and prime editing (BE and PE) approaches to correct to correct at DNA level the most frequent RTT causative mutations. These approaches offer the possibility to maintain the tight MECP2 regulation, have higher efficiency with low off-target effects, can install programmed edits even in non-dividing cells and the modification is maintained over time. Both approaches are compatible with viral and non-viral delivery approaches, with experimental evidences also in central nervous system. In this one-year project we will exploit cellular models, also from RTT patients, to design efficient BE and PE, and to evaluate their specificity/off-target effects. The project, will provide the proof-of-concept that BE and PE can ensure effective and stable reconstitution of the natural MECP2 expression with a single intervention, thus paving the ground for future and extensive studies in the available RTT mouse models aimed at evaluating the therapeutic potential of BE and PE for RTT as well as other neurological diseases.