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Hepcidin, a 25-amino-acid antimicrobial peptide, is the central regulator of iron homeostasis. Hepcidin transcription is upregulated by inflammatory cytokines, iron, and bone morphogenetic proteins and is downregulated by iron deficiency, ineffective erythropoiesis, and hypoxia. The iron transporter ferroportin is the cognate receptor of hepcidin and is destroyed as a result of interaction with the peptide. Except for inherited defects of ferroportin and hepcidin itself, all forms of iron-storage disease appear to arise from hepcidin dysregulation. Studies using multiple approaches have begun to delineate the molecular mechanisms that regulate hepcidin expression, particularly at the transcriptional level. Knowledge of the regulation of hepcidin by inflammation, iron, erythropoiesis, and hypoxia will lead to an understanding of the pathogenesis of primary hemochromatosis, secondary iron overload, and anemia of inflammatory disease.

Juvenile hemochromatosis is an earlyonset form of iron storage disease characterized by hypogonadotrophic hypogonadism and cardiomyopathy. Recently, the putative causative gene (LOC148738) encoding a protein designated hemojuvelin was cloned. The previously proposed designation of this gene as HFE2 is contrary to established convention, because it is not a member of the HFE family. We suggest that it be designated HJV. We sequenced this gene in members of 2 previously reported kinships that manifest typical juvenile hemochromatosis. In one kinship, 2 previously undescribed mutations of HJV were identified, c.238T>C (C80R) and c.302T>C (L101P). In the second kinship, 2 previously identified mutations, G320V and I222N, were found. These studies confirm that mutations in HJV cause juvenile hemochromatosis. (Blood.

The predominant genetic defect causing p47-phox -deficient chronic granulomatous disease (A47 Њ CGD) is a GT deletion ( ⌬ GT) at the beginning of exon 2. No explanation exists to account for the high incidence of this single mutation causing a rare disease in an unrelated, racially diverse population. In each of 34 consecutive unrelated normal individuals, both the normal and mutant ⌬ GT sequences were present in genomic DNA, suggesting that a p47-phox related sequence carrying ⌬ GT exists in the normal population. Screening of genomic bacteriophage and YAC libraries identified 13 p47-phox bacteriophage and 19 YAC clones. The GT deletion was found in 11 bacteriophage and 15 YAC clones. Only 5 exonic and 33 intronic differences distinguished all ⌬ GT clones from all wild-type clones. The most striking differences were a 30-bp deletion in intron 1 and a 20-bp duplication in intron 2. These results provide good evidence for the existence of at least one highly homologous p47-phox pseudogene containing the ⌬ GT mutation.

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