In vitro, oligodendrocytes of Abcd1 null mice showed increased death rate during induced demyelination.19 Biochemically, elevated VLCFA levels are noted across various tissues, including a 2–8-fold increase in hexacosanoic acid,5,20 yet no diminution in peroxisomal β-oxidation activity was evidenced in mouse fibroblasts,21 as opposed to human fibroblasts.22 Additionally, these models do not exhibit adrenal pathology analogous to that seen in human X-ALD. The gene discussed is ABCD1; the disease is X-linked adrenoleukodystrophy.