Aceruloplasminemia in a Japanese woman with a novel mutation of CP gene: clinical presentations and analysis of genetic and molecular pathogenesis.

We report a Japanese woman diagnosed as aceruloplasminemia showing characteristic symptoms. Mutational analysis of CP gene revealed a novel homozygous mutation in exon 18, resulting in prematurely truncated W1017X protein. In vitro study showed that W1017X mutant ceruloplasmin was deficient in endoplasmic reticulum to Golgi trafficking and was not secreted to medium. It has been reported that the presence of both the G (FLI/LI) GP domain and the 881th cysteine residue was sufficient for secretion. Thus, our report on this novel mutant indicates the previously unreported importance of carboxy-terminus residues in the secretion pathway.