We report a familial case of hereditary ceruloplasmin deficiency (HCD) showing an A-G transition in intron 6 of the ceruloplasmin gene. Clinical features consisted of chorea, cerebellar ataxia, dementia, diabetes mellitus, retinal pigmentation and iron deposition in the liver and brain without copper overload in those organs. The patient's children and siblings had similar laboratory results, but did not show any neurological abnormalities. She was medicated for diabetes mellitus at 43 years of age, and neurological signs appeared when she was 52 years old. The laboratory findings were anemia, low concentrations of iron and copper in serum and of copper in urine. Ceruloplasmin was not detected in the serum. The iron and copper contents in the liver were 3,580 and 10 microg/g wet tissue, respectively. MRI of the brain showed iron deposition in the basal ganglia, dentate nucleus and thalamus. This case did not show any abnormal increase in copper in the blood and urine following CuSO(4)5H(2)O oral overloading test. Following the intravenous administration of commercially available fresh-frozen human plasma (FFP) containing ceruloplasmin, the serum iron content increased for several hours due to ferroxidase activity of ceruloplasmin. In the liver, the iron content decreased more with the combined intravenous administration of FFP and deferoxamine than with FFP administration alone. Her neurological symptoms improved following repetitive FFP treatment.