Noonan syndrome is a genetic disorder linked to germline mutations in the RAS-MAPK pathway, all leading to a hyperactivation of the signaling cascade. With a prevalence of 1 in 1.000 to 2.500 live births, Noonan syndrome is considered the most common monogenetic disease associated with congenital heart defects, such as hypertrophic cardiomyopathy. Further, pathogenic variants in LZTR1 are particularly linked to a severe and early-onset hypertrophic cardiomyopathy. Despite high clinical relevance, therapeutic options remain limited and curative therapy options are urgently needed. Personalized CRISPR-based strategies may offer curative treatment options for Noonan syndrome patients. Advanced CRISPR-based gene editing techniques allow precise correction of disease-causing mutations in terminally differentiated cells, such as cardiomyocytes. In this study, we employed different clinically translatable adenine base editing strategies to correct one of the most common Noonan syndrome-associated LZTR1 variants in iPSC-cardiomyocytes derived from different Noonan syndrome patients. All-in-one AAV adenine base editing efficiently corrected the disease-causing LZTR1 variant, resulting in restoration of LZTR1 function and rescue of the disease pathology at molecular level in 2D and 3D patient-specific cardiac models.
