A comparison of erythrocytes, lymphocytes and blood plasma as samples in fatty acid analysis for the diagnosis of adrenoleukodystrophy

Diagnosis of X-linked adrenoleukodystrophy in blood leukocytes

OBJECTIVES

Our aim was to replace cultured skin fibroblasts in the diagnosis of X-linked adrenoleukodystrophy (X-ALD) by peripheral blood cells.

DESIGN AND METHODS

Very long chain fatty acids (VLCFAs) were analyzed in leukocytes from X-ALD patients, heterozygotes, and controls using gas chromatography-mass spectrometry (GC-MS). Immunofluorescence for adrenoleukodystrophy protein (ALDP) was performed in mononuclear blood cell preparations of X-ALD patients known to be ALDP negative in fibroblasts, heterozygote relatives of these patients, and controls.

RESULTS

All X-ALD patients were distinguishable from controls by VLCFA analysis in leukocytes. 91.7% of heterozygotes were identified by combined VLCFA analysis in leukocytes and plasma. All patients investigated lacked ALDP immunoreactivity in mononuclear cells, while heterozygotes showed mosaic patterns of positive and negative cells.

CONCLUSION

Determination of VLCFAs by GC-MS in combination with ALDP immunofluorescence in peripheral blood cells provides a fast and minimally invasive diagnostic method for X-ALD, which, in contrast to plasma analysis, is independent of alimentary influences. Notably, joint evaluation of leukocytes and plasma considerably improves the identification of heterozygotes.

Correlations of elevated levels of hexacosanoate in erythrocyte membranes with risk factors for atherosclerosis

We analyzed erythrocyte membrane C26:0 from 504 volunteers by high-performance liquid chromatography. The associations between the elevated levels of erythrocyte membrane C26:0 (0.20 or greater than 0.20%) and sex, obesity (body mass index> or =26.4), smoking (> or =20 cigarettes per day), present illnesses and past diseases were examined with the chi(2) test. The correlations among age and the levels of erythrocyte membrane C26:0, plasma total cholesterol, triglycerides, LDL cholesterol and HDL cholesterol were analyzed using Spearman's correlation coefficient. Moreover, the frequencies of high levels of erythrocyte membrane C26:0 were examined in male and female subjects divided into seven age groups. The elevated levels of erythrocyte membrane C26:0 were significantly more frequent in male subjects than in females, and were closely associated with obesity, smoking, and atherosclerosis-related diseases of present illnesses. The levels of erythrocyte membrane C26:0 were highly correlated with age and the levels of plasma total cholesterol, triglycerides and LDL cholesterol, and inversely with those of HDL cholesterol. The frequency of high levels of erythrocyte membrane C26:0 in male subjects was greater than that in female subjects in all of the seven age groups. Elevated levels of erythrocyte membrane C26:0 may be closely related with atherosclerosis.

Characterization of X-linked adrenoleukodystrophy in different biological specimens from ten Portuguese families

X-linked adrenoleukodystrophy (ALD) is a severe neurodegenerative disease characterized by progressive demyelination, adrenocortical insufficiency and accumulation in tissues and body fluids of unbranched, saturated very long-chain fatty acids (VLCFA). The diagnosis of ALD is usually based on clinical history, neurological examination and the determination of levels of VLCFA in plasma and cultured skin fibroblasts. In the present paper we report the biochemical findings in plasma, cultured skin fibroblasts and lymphoblastoid cell lines from ALD patients. The results obtained indicate that the increment of the ratios C24:0 to C22:0 and C26:0 to C22:0 and of the concentration C26:0 (micrograms/ml) in plasma was parallel with that of fibroblasts, but not with that of Epstein-Barr virus (EBV)-transformed lymphocytes, suggesting that this cell line is not reliable for diagnosis of ALD by VLCFA analysis. Subsequent studies carried out on family members revealed heterozygotes other than obligate carriers and hemizygotes who were pre-symptomatic or had a misdiagnosis of multiple sclerosis or psychosis.

Adrenoleukodystrophy: a correlation between saturated very long-chain fatty acids in mononuclear cells and phenotype

Saturated very long-chain fatty acids in erythrocyte membranes, blood plasma, and mononuclear cells were studied in 4 patients with childhood-adolescent adrenoleukodystrophy and 4 patients with adult adrenoleukodystrophy and 19 normal control subjects by using high-performance liquid chromatography. Ratios of C26:0 to C22:0 in mononuclear cells, erythrocyte membranes, and blood plasma in patients with childhood-adolescent and adult adrenoleukodystrophy were significantly higher than in normal control subjects. Furthermore, ratios of C26:0 to C22:0 in mononuclear cells were significantly higher in patients with childhood-adolescent adrenoleukodystrophy than in patients with adult adrenoleukodystrophy, whereas there was no significant difference in the ratios in erythrocyte membranes and blood plasma between the two groups of patients with adrenoleukodystrophy. These results suggest that there is a correlation between phenotype and ratio of C26:0 to C22:0 within mononuclear cells in patients with adrenoleukodystrophy.