Concerning X-ALD, it has long been established that ABCD1 deficiency leads to the accumulation of VLCFAs, cholesteryl esters and also membrane lipids (PC, SM, gangliosides, myelin), as observed in erythrocytes [121, 122], fibroblasts [123], myelin [124] or brain tissues [125, 126] of X-ALD patients. Here, ABCD1 is linked to X-linked adrenoleukodystrophy.