A case of aceruloplasminemia presenting as cerebellar ataxia with homozygous mutation nt2602 delG]

Aceruloplasminemia is an autosomal recessive disorder of iron metabolism caused by mutations in the ceruloplasmin (Cp) gene. We reported the results of clinical and molecular studies on a Japanese family with aceruloplasminemia. A 58-year-old man who had had diabetes mellitus for more than 30 years developed cerebellar ataxia several years before. He was found to have mild retinal degeneration too. Laboratory findings revealed a complete deficiency of serum ferroxidase activity and undetectable serum Cp. Magnetic resonance imaging showed a pronounced hypointensity in the bilateral putamina, caudate, thalamus and dentate nuclei on both T1- and T2-weighted images suggesting the presence of iron overload. We identified a homozygous deletion mutation (nt2602 delG) of the Cp gene in the patient, and the same heterozygous mutation in his unaffected father. To date, at least 29 mutations in the Cp gene have been identified. Although an individual with a heterozygous mutation has been believed to be an asymptomatic carrier like his father, some patients with such a condition were recently described to show neurological deficits. The variation in clinical findings may be explained partly by the difference in the severity of generation of free radicals caused by iron deposition or the environmental factors such as aging. Further investigations would be required to elucidate the molecular mechanisms of this late onset neurodegeneraion.