During the year 1995-1996, the Outpatient GCRC has been of indispensable value for the follow-up of men with adrenomyeloneuropathy (AMN). This follow-up study has four major objectives: 1) Define the phenotype and clinical course in untreated AMN patients. We had found in the previous year, with the support of the OPD-GCRC, that AMN can be subdivided into two major categories on the basis of Magnetic Resonance Imaging (MRI) studies. The AMN patients with normal MRI have essentially normal cognitive function and an excellent long- term prognosis. The peripheral nerve abnormalities in AMN are attributable mainly to axonal involvement rather than demyelination. 2) Clarify the pathogenesis of Adrenoleukodystophy (ALD). The main significant finding during the last year was the demonstration that the inflammatory demyelinating lesions in the rapidly progressive forms of ALD differ from those in multiple sclerosis in respect to cytokine pattern and HLA linkage. The nature of the inflammatory response was also clarified by the application of the magnetization transfer imaging technique. 3) A major goal of the studies is the evaluation of dietary therapy with "Lorenzo's Oil". This study required precise knowledge or the natural progression of the disease (the topic of objective 1), and a multidisciplinary appraisal of the clinical course in treated patients. This is in progress. 4) It has been noted that a moderate reduction of platelet count is a common side effect of Lorenzo Oil therapy. As reported in publication 5, we have shown that the reduction of platelet count is correlated with the level of erucic acid in platelets. This study has provided us with a strategy to monitor and manage this side effect.