Representative traces of tetanic force (150 Hz, Figure 1D) also demonstrated myotonia, as evidenced by delayed muscle relaxation in ClC-1–/– (blue trace) and CaV1.1Δe29 ClC-1–/– (red trace) muscle, which was absent in WT (black trace) and CaV1.1Δe29 (orange trace) controls. The gene discussed is CLCN1; the disease is Myotonia.