Mean MR spectra from basal ganglia during metabolic stability and acute encephalopathy in propionic acidaemia. (A) Metabolically stable and (B) acutely encephalopathic propionic acidaemia patients compared to normal imaging comparator cohort. ppm, parts per million; a.u., arbitrary units. Major metabolite peaks identified (labelled arrows), significant differences indicated by *. Glx, glutamine + glutamate; Ins, myo-inositol; Cre, Creatine; NAA, N-acetylaspartate; Lac, lactic acid.