Hereditary ceruloplasmin deficiency with hemosiderosis (aceruloplasminemia) is a new disease characterized by systemic hemosiderosis, diabetes mellitus, neurological abnormalities and pigment degeneration of the retina. Loss of the ferroxidase activity of ceruloplasmin results in systemic iron deposition and tissue damage. Neuroimaging studies reveal iron deposition in basal ganglia and in the red and dentate nuclei. Cerebellar ataxia, extrapyramidal signs and dementia develop after middle age. We report a patient with undetectable serum ceruloplasmin levels and the above clinical manifestations. Sequence analysis of the cDNA of ceruloplasmin from this patient revealed an insertion of adenine in exon 3; this produced a premature stop codon.