ABCD1 is critical for the peroxisomal import of very long fatty acids and related CoA esters for catabolism through β-oxidation, and mutations in this gene are responsible for adrenoleukodystrophy, an X-linked and neurodegenerative disorder associated with microglial apoptosis (Eichler et al, 2008). The gene discussed is ABCD1; the disease is adrenoleukodystrophy.