The degree of demyelination in adrenoleukodystrophy is related to the Pentacosanoic to Docosanoic acid ratios (C25:0/C22:0 and C26:0/C22:0). Mainly saturated fatty acids of the middle class components (C24:0, C25:0 and C26:0) are found in severely affected areas where the active process is complete. Because a region of high long chain fatty acid content, lacking histopathological change, is detected.
The area with myelin destruction with axonal preservation is generally most prominent in the frontal edge of the lesion. A bell-shaped distribution of very long chain fatty acids, esterified to cholesterol, are detectable, with the mid-point being formed by Pentacosanoic (C25 : 0) and Hexacosanoic (C26 : 0) acids.