X-linked adrenoleukodystrophy (ALD) is a genetically determined metabolic disorder that manifests clinically as dysfunctions of the central nervous system (CNS), adrenal glands and testes. These dysfunctions are related to excessive accumulation of very long chain fatty acid (VLCFA) in tissues and plasma, which is caused by the failure of oxidative degradation of VLCFA that normally takes place in peroxisomes. There is widespread demyelination of white matter (particularly bilateral parieto-occipital region) with inflammatory reaction and atrophy of adrenal cortex.