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

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 MYBPC3. The deletion was corrected with CRISPR/Cas9 in the patient-specific iPSCs. The iPSC lines with the corrected deletion in MYBPC3 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 MYBPC3 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 MYBPC3, 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.