[X-linked adrenoleukodystrophy and other peroxisomal diseases caused by a failing peroxisomal beta-oxidation system: clinical expression, diagnosis and treatment].

X-linked adrenoleukodystrophy (ALD) is a sex-linked, neurodegenerative disorder which in its most stereotypic form manifests itself in a boy who progresses normally for the first years of life and then presents with CNS signs and symptoms such as behavioural abnormalities, visual and auditory disturbances and an abnormal gait. The course of the disease is progressive, culminating within a few years in dementia, blindness, quadriplegia and death. Recently it has become clear that ALD is caused by an impairment in the peroxisomal beta-oxidation system leading to the accumulation of very-long-chain fatty acids. Accumulation occurs not only in plasma but also in brain giving rise to increasing myelin instability and subsequent demyelination. Apart from X-linked ALD there are a number of other disorders all characterized by a deficient peroxisomal beta-oxidation activity. It is remarkable that the clinical presentation of these different inborn errors of peroxisomal beta-oxidation differs markedly. In this paper the inborn errors of peroxisomal beta-oxidation known at present will be discussed with particular emphasis on ALD.