Type 2 haemochromatosis is known as a juvenile-onset disorder because symptoms often begin in childhood.

This type of haemochromatosis results is a rare autosomal recessive disorder caused by mutations in the HJV gene (type 2A) that affect the transcription protein hemojuvelin or mutations in the HAMP gene (type 2B), which directly codes for hepcidin.

This type of GH normally present before the age of 30 and affected individuals are at high risk of developing target organ damage, including cardiomyopathy (disorder that affects the heart muscle). Although often more severe, the phenotype of type 2 GH closely resembles that of type 1 since both conditions are associated with reduced expression of the principal iron regulatory protein hepcidin.

If this type of GH is suspected in which ferritin and iron blood tests indicate iron overload and genetic testing is negative for the HFE gene mutation, particularly in younger patients, further genetic testing is required for HJV and HAMP genes.

Once a patient with type 2 has been identified, family screening of all first-degree relatives should commence. It is recommended that biochemical (ferritin and transferrin saturation blood tests) and genetic testing be performed.

We have two special guides for children (and their parents or guardians) about genetic haemochromatosis.