El gen de expresion de la HJV esta ubicado en el cromosoma 1q21 y es tambien conocido como HJV o HFE2 (por ser responsable de la hemocromatosis juvenil).
Mutations in HFE2 cause iron overload in chromosome 1qlinked juvenile hemochromatosis.
 Human genes: TMPRSS6, transmembrane protease, serine 6; HFE, hemochromatosis; PER1, period homolog 1 (Drosophila); TIMELESS, timeless homolog (Drosophila); CLOCK, clock homolog (mouse); HAMP, hepcidin antimicrobial peptide; TFR2, transferrin receptor 2; HFE2
, hemochromatosis type 2 (juvenile).
Hemojuvelin is a protein encoded by a gene initially named HFE2 but later designated HJV because it is not a member of the HFE family but instead is related to the repulsive guidance molecule family of proteins.
Mutations in HFE2 cause iron overload in chromosome 1q-linked juvenile hemochromatosis.
Mutations in hepcidin (HAMP) and or haemojuvelin (HJV, also known as HFE2
) genes are implicated in the disease process.
Juvenile hemochromatosis (JH) is due to a mutation in 1 of 2 genes: HFE2 [hemochromatosis type 2 (juvenile); also known as HJV and encoding hemojuvelin] (7) and, more rarely, HAMP (hepcidin antimicrobial peptide) (8).
We first targeted HFE and TFR2 genes in group 1A and preferentially screened HAMP and HFE2 genes in group 113.
GenBank sequence accession numbers for the SLC40A1, FTL, HFE, HFE2, HAMP, and TFR2 genes are NC 000002.10, NC_000019.8, NC_000006.10, NC_000001.9, NC_000019.8, and NC_000007.12, respectively.
However, most workers in the field of iron metabolism do not approve with this classification because (a) it is neither genotypic nor phenotypic, but rather a mixture of the two; (b) it leaves no space for recently identified atypical cases that are related to combinations of sequence variations (106,148-152); (c) it sets up hypothetical genes, e.g., HFE1, HFE2, HFE3, and so forth, when its not really a gene family at all; and finally (d) there are also other forms of hemochromatosis that are not included in the OMIM classification (Table 2).
Mutations in HFE2 cause iron overload in chromosome 1g-linked juvenile hemochromatosis.
 Human genes: HFE, hemochromatosis; HJV (alias, HFE2), hemochromatosis type 2 (juvenile); HAMP, hepcidin antimicrobial peptide (alias, LEAP-1); SMAD4, mothers against DPP homolog 4 (Drosophila); TfR2, transferrin receptor 2 (alias, HFE3); SLC40AI, solute carrier family 40 (iron-regulated transporter), member 1 (aliases, IREG1, FPN1, HFE4); FTL, L-ferritin; and SLCIIA2, solute carrier family 11 (proton-coupled divalent metal ion transporters), member 2 (aliases, DMT1, DCT1, and NRAMP2).