ABCD1 and X-linked adrenoleukodystrophy: Peroxisomal metabolism is essential to myelin turnover and maintenance, and disorders ofperoxisomal function have characteristic severe white matter lesions of the nervous system.X-linked adrenoleukodystrophy (X-ALD), the most common peroxisomal disorder, is caused bymutations in the ATP-binding cassette transporter D1 (ABCD1) gene.