NPPA and early-onset autosomal dominant Alzheimer disease: Alterations in KP metabolism have been implicated in the pathophysiology of a variety of CNS inflammatory diseases including; Alzheimer’s disease,8–10 Multiple Sclerosis,11 Parkinson’s,12 Cerebral Malaria,13 Amyotropic lateral sclerosis14 and HIV infection.15 It is therefore reasonable to consider whether changes in PIC levels also correlate with either cellular or clinical pathology in any of these conditions.