Defective electron transfer in complexes I and IV in patients with aceruloplasminemia.

Aceruloplasminemia is a disorder of iron metabolism caused by mutations in the ceruloplasmin gene. It is characterized by progressive neurodegeneration of the retina, basal ganglia, dentate nucleus and cerebral cortex in association with iron accumulation in these tissues. Enzyme activities in the mitochondrial respiratory chain of the cerebral cortices of two patients were reduced to 62% and 71% for complexes I and IV. Malondialdehyde, a marker of lipid peroxidation, was three times higher than the control value and was accompanied by increased expression of superoxide dismutase 2 (Mn SOD). These findings suggest that iron-mediated free radicals contribute to the impairment of mitochondrial energy metabolism in aceruloplasminemia