ABCD1 and X-linked adrenoleukodystrophy: The function of ABCD1 substrate as a straight-chain saturated fatty acid was confirmed during the transfection of human ABCD1 reverse-transcription DNA into X-ALD skin fibroblasts to restore the oxidative activity of VLCFA-β and the VLCFA content in fibroblasts to normal cell levels.12–14 Van Roermund et al. proved that ABCD1 is involved in the transport of VLCFA-CoA through the peroxisome membrane to express human ABCD1 in Saccharomyces cerevisiae.