Previous studies have used a wide range of in vitro, in vivo, and clinical investigational systems, such as patient-derived fibroblasts [5,29,30], rat hippocampal cell cultures of oligodendrocytes and astrocytes [4], established oligodendrocyte cell lines [31,32], Abcd1 genetic deficient mouse models [33], and patients showing the varied clinical presentations of ALD [34,35]. Here, ABCD1 is linked to X-linked adrenoleukodystrophy.