TNNT2 and Arrhythmia: The percentage of cTnT positive cells in this arrhythmia model was 25 ± 6% (n = 4) for the 409B2 control, 41 ± 10% (n = 4) for the SQT22 mutant, and 29 ± 15% (n = 4) for the LQT26 mutant (Supplementary Fig. 8b).