Figure 2.

(A) Typical example of a permeabilized muscle fiber preparation of a control subject (left) and of two NEM3 patients (middle and right) mounted in the contractility setup. (B) Typical tracing showing the force response to incremental Ca²⁺ concentrations followed by the measurement of the rate constant redevelopment (k_tr) and the active stiffness in a control and a NEM3 patient (P5); (C) Maximal active tension (force normalized to CSA), k_tr (D), active stiffness (E), and the tension stiffness ratio (F) were significantly lower in NEM3 patients than in control subjects; (G) Force-pCa relationship showing the average of all controls (n=7) and all NEM3 patients (n=14), showing no difference in mean calcium sensitivity between the groups. However, analyzing individual patients illustrated that some patients have increased and some decreased pCa₅₀(H); ‘normal range’: mean of controls +/− ± 2*SD. The Hill coefficient, n_H (I), was significantly decreased compared to control subjects. Note: slow-twitch fibers in light color, fast-twitch fibers in dark color, bundle of mixed fiber-types in intermediate color (only in NEM3 patients).