CARRIER IDENTIFICATION OF X-LINKED ADRENOLEUKODYSTROPHY BY MEASUREMENT OF VERY LONG-CHAIN FATTY-ACIDS AND LIGNOCERIC ACID OXIDATION

Because identification of carriers of X-linked adrenoleukodystrophy (A LD) results in 5-15% false negatives with very long chain fatty acids (VLCFA) assay in plasma, and mutation analysis of the ALD gene is not always practical, we studied whether the analysis of plasma VLCFA comb ined with lignoceric acid oxidation study in fibroblasts could improve the rate of carrier detection. Lignoceric acid oxidation was abnormal in 19 out of 19 patients (ALD or adrenomyeloneuropathy) and in three out of three obligate heterozygous women. Among ten women at risk of b eing a carrier, three women who had normal plasma VLCFA had abnormal l ignoceric acid oxidation in fibroblasts. These data suggest that this combined biochemical procedure may help to improve carrier detection i n families when the ALD gene mutation has not been identified.