ABCD1 and X-linked adrenoleukodystrophy: To date, the X‐ALD Mutation Database (http://www.x‐ald.nl) has cataloged over 3700 ABCD1 gene variants, predominantly comprising missense mutations (63.8%), nonsense mutations (9.1%), frameshift mutations (15.7%), splice site mutations (4.0%), and exon deletions (2.5%).