Peroxisomal disorders are genetic
metabolic diseases with generalized, multiple, or single functional disturbances of the peroxisome. According to the extent of the functional disturbances 3 groups of diseases can be differentiated: disorders with generalized loss of peroxisomal functions (
Zellweger syndrome, ZS;
neonatal adrenoleukodystrophy, NALD;
infantile Refsum's disease), disorders with multiple enzymatic defects (e.g.
rhizomelic chondrodysplasia punctata), and disorders with a single enzymatic defect in the peroxisome, the most important being
adrenoleukodystrophy/
adrenomyeloneuropathy (ALD/AMN). Adult
Refsum's disease, a genetic
neurological disorder with
phytanic acid accumulation, is due to a mitochondrial
enzyme deficiency, but is often considered together with peroxisomal diseases because of
phytanic acid (PHYT) accumulation in most peroxisomal diseases. The main clinical and pathological criteria of the major disorders and the biochemical parameters of their differentiation are presented. Elevated levels of very long chain
fatty acids (VLCFA) and/or PHYT are the primary diagnostic markers for all
peroxisomal disorders and adult
Refsum's disease, respectively. Our investigations disclosed 30 ALD/AMN hemizygotes, 16 ALD/AMN heterozygotes, 8 cases of ZS/NALD and 7 patients with adult
Refsum's disease. In addition, 15 cases of
peroxisomal disorders were confirmed by biochemical investigations in autopsy material. With regard to
peroxisomal disorders, therapeutic concepts exist only for ALD/AMN:
corticosteroid substitution for
adrenal insufficiency, dietary treatment, and
bone marrow transplantation (BMT). Adult
Refsum's disease can be treated successfully by dietary
therapy. In case of dietary treatment and BMT, assay of VLCFA and/or PHYT is important for the biochemical evaluation of these
therapies.