X-linked adrenoleukodystrophy gene: identification of a candidate gene by positional cloning.

Adrenoleukodystrophy (ALD) is an X-linked peroxisomal disorder characterized by a progressive demyelination of the central nervous system, adrenal insufficiency and impaired capacity to o-oxidase very long chain fatty acids, a metabolic process that normally takes place in peroxisomes. The ALD locus has been mapped to Xq28 and we have recently identified a patient with ALD who has a complex rearrangement in the 5' end of the red/green color pigment genes in Xq28. This rearrangement comprises two deletions separated by a large inversion. The second deletion of this key ALD patient extends 19 kb into the 3' region of an expressed gene which was found partially deleted in six of 85 independent patients with ALD. This segment thus constitutes a candidate region for the ALD gene.