Generation of Isogenic iPSC Lines for Studying the Effect of the p.N515del (c.1543_1545delAAC) Variant on MYBPC3 Function and Hypertrophic Cardiomyopathy Pathogenesis.

The clinical significance of numerous cardiovascular gene variants remains to be determined. CRISPR/Cas9 allows for the introduction and/or correction of a certain variant in induced pluripotent stem cells (iPSCs). The resulting isogenic iPSC lines can be differentiated into cardiomyocytes and used as a platform to assess the pathogenicity of the variant. In this study, isogenic iPSC lines were generated for a variant of unknown significance found previously in a patient with hypertrophic cardiomyopathy (HCM), p.N515del (c.1543_1545delAAC) in . The deletion was corrected with CRISPR/Cas9 in the patient-specific iPSCs. The iPSC lines with the corrected deletion in maintained pluripotency and a normal karyotype and showed no off-target CRISPR/Cas9 activity. The isogenic iPSC lines, together with isogenic iPSC lines generated earlier via introducing the p.N515del (c.1543_1545delAAC) variant in of iPSCs of a healthy donor, were differentiated into cardiomyocytes. The cardiomyocytes derived from both panels of the isogenic iPSCs showed an increased size in the presence of the deletion in , which is one of the HCM traits at the cellular level. This finding indicates the effectiveness of these iPSC lines for studying the impact of the variant on HCM development.