Energy-generating capacity of intact fibroblasts measured as CO2 and ATP production. The energy-generating capacity of fibroblasts was assayed as described in Patients and methods section using either pyruvate+malate (a, c) or succinate+acetylcarnitine (b, d) as substrates and measuring either CO2 (a, b) or ATP production (c, d). Results of unpaired t-tests with Welch's correction are show. ns, not significant; *P=0.013; ***P=0.001.