ABCD1 and X-linked adrenoleukodystrophy: Adrenoleukodystrophy (ALD) is an X-linked demyelinating leukodystrophy caused by mutation in the ABCD1 gene (Mosser et al., 1993), which encodes an ATP-binding cassette transporter necessary for very long-chain fatty acid (VLCFA) transport into the peroxisome for degradation (McGuinness et al., 2003; van Roermund et al., 2011; Wiesinger et al., 2013).