Two transferrin receptors, TfR1 and TfR2, sense the plasma iron that convey the information to the BMP receptor complex via the additional proteins HFE and haemojuvelin
(HJV).2,7,16-18 BMP6 activates the intracellular S-mothers against decapentaplegic (SMAD) pathway, which in turn up-regulates the HAMP promoter to synthesise hepcidin.
Under the terms of the agreement, Isis received an undisclosed upfront payment in the form of a convertible promissory note from Xenon to discover and develop antisense drugs to the targets hepcidin and haemojuvelin
. Upon the identification of a development candidate, Xenon has the option to exclusively license the development and worldwide commercialisation rights for these antisense drugs from Isis.
There is some phenotypic variation with haemojuvelin, hepcidin or ferroportin mutations presenting at an earlier age.
This is a severe autosomal recessive condition, leading to early and profound overload with two subtypes--the first involving the hepcidin regulatory protein known as haemojuvelin. In the second the mutation is in the hepcidin gene itself.
Mutations in hepcidin (HAMP) and or haemojuvelin
(HJV, also known as HFE2) genes are implicated in the disease process.