Here, we demonstrated that distinct clinical phenotypes of X‐ALD are associated with increased levels of transcriptional inhibitors of myelin gene expression (ie, ID4 and SOX2) and the resulting decreased levels of genes associated with the mature differentiated phenotype (ie, MBP, MOBP, MOG, MAG, NINJ2, OPALIN, OLIG1, CNP and PLP1). This evidence concerns the gene NINJ2 and adrenoleukodystrophy.