P-31-NMR SPECTROSCOPY OF SKELETAL-MUSCLE IN BECKER DYSTROPHY AND DMD BMD CARRIERS - ALTERED RATE OF PHOSPHATE-TRANSPORT

Muscle energy metabolism was studied by phosphorus nuclear magnetic resonance spectroscopy (P-31-NMR) in 6 patients with Becker dystrophy, and in 24 female DMD/BMD carriers (n = 18) and non-carriers (n = 6). At rest all patients showed a high P(i)/PCr ratio due to low PCr and high P(i) contents, and a high intracellular IpH. P-31-NMR of carriers and non-carriers did not differ from controls. In patients and carriers in-magnet exercise revealed a reduced ability to perform work and P(i)/PCr ratios higher than controls for comparable relative levels of steady-state work. Post-exercise P(i) recovery was found abnormal in patients and in carriers. The P-31-NMR abnormalities found in thc working muscle of both BMD patients and female DMD/BMD carriers indicate a defect of phosphate metabolism that, be it primary or secondary, reflects a deficit of energy metabolism.