ABCD1 and X-linked adrenoleukodystrophy: Alterations in peroxisomal function are also suspected of contributing in the etiology of various neurodegenerative diseases: (a) multiple sclerosis: high concentrations of C26:0 are present in grey matter as well as in serum [1,2], (b) Alzheimer’s disease: there is an accumulation of C22:0, C24:0 (tetracosanoic acid or lignoceric acid) and C26:0 [3], (c) X-linked adrenoleukodystrophy (X-ALD): there is an accumulation of C24:0, C26:0 and C26:1, in tissue and plasma caused by mutations in the ABCD1 gene, (d) dementia: there are higher levels of C26:0 in the plasma and red blood cells [4].