Map of the 5′-UTR region of the HAMP gene. The normal hepcidin peptide is derived from the C-terminus of an 84 amino acid prepropeptide, encoded by a 0.4-kb mRNA, generated from 3 exons of a 2.5-kb gene on chromosome 19. The G → A mutation at position +14 creates a new AUG codon, which leads to a shift of the reading frame, inhibition of the synthesis of the normal hepcidin protein, and probably generation of a new abnormal protein instead. Kozak sequences are underlined. The initiation codon AUG is given in bold.