X-linked adrenoleukodystrophy is both the most frequent genetically inherited demyelinating disorder and the most frequent peroxisomal disorder. It shows extreme clinical heterogeneity, even within the same kindreds. Adrenal insufficiency (Addison's disease) is probably the only clinical manifestation of adrenoleukodystrophy while the main biochemical abnormality of adrenoleukodystrophy is an impairment of very long chain fatty acid (VLCFA)b-oxidation in the peroxisomes, resulting in the accumulation of VLCFA cholesterol esters in the adrenal gland and in the white matter of the brain.
Defects in ATP-Binding Cassette Subfamily D Member 1 (ABCD1) gene are the cause of the condition.