Diagnostic patterns of very-long-chain fatty acids in plasma of patients with X-linked adrenoleukodystrophy

Pattern recognition analysis on the levels of the very-long-chain fatty acids (VLCFAs) in plasma is described for the visual discrimination of X-linked adrenoleukodystrophy (X-ALD) patients from normal healthy group. Plasma VLCFA compositions of 58 normal subjects and 16 X-ALD patients were examined by gas chromatography as their methyl esters to determine the area percentages of behenic acid (C22:0), lignoceric acid (C24:0) and hexacosanoic acid (C26:0) in the total fatty acids, and the concentration (microg/ml) of C26:0. When star symbol plotting was applied to the VLCFA values of C22:0 (%), C24:0 (%), C26:0 (%), C24:0/C22:0, C26:0/C22:0 and C26:0 (microg/ml) after normalization to the corresponding median values in normal group, the resulting deformed hexagonal star pattern was characteristic of each patient. Therefore, simple visual comparison with the equilateral hexagon of normal group average as the control pattern enabled one readily to discriminate X-ALD patients from the normal group. Additionally, canonical discriminant analysis performed on the six unnormalized VLCFA values correctly classified 74 plasma specimens into two separate clusters according to normal subject or X-ALD patient in the canonical plot.