Failure of muscle energy metabolism in a patient with adenylsuccinate lyase deficiency - An in vivo study by phosphorus NMR spectroscopy

P-31-nuclear magnetic resonance spectroscopy was used to investigate in vivo the energy metabolism of the calf muscle in a 10-year-old patient with adenylosuccinate lyase deficiency and severe psychomotor retardation, The patient showed a markedly reduced PCr/P-i molar ratio, known to well represent the cytosolic phosphorylation potential, due to low PCr and high P-i content in resting muscle. Moreover, intracellular ATP concentration was significantly lower than in the control group both at rest and at the end of post-exercise recovery. The rate of patient's PCr recovery after an exercise in ischaemic conditions was also out of the reference range, suggesting a reduced ability of mitochondria to respond to metabolic needs. (C) 1997 Elsevier Science B.V.