Juvenile haemochromatosis.

Juvenile haemochromatosis is a severe inherited iron-loading disorder that can present in children and adolescents. Typical manifestations include heart failure, endocrine failure (including diabetes and hypogonadism), cirrhosis, and arthropathy. Compared with HFE haemochromatosis, juvenile haemochromatosis affects female and male individuals similarly, presents at a younger age, and causes multiple organ dysfunction; the principle of iron loading into tissues from the gut is shared by both forms, but the process is far more rapid in juvenile haemochromatosis. Juvenile haemochromatosis is initially recognised by extreme increases of serum ferritin and transferrin saturation, which is supported by an MRI showing iron deposition in the heart and liver. MRI software techniques allow quantification of iron in these organs, and can therefore be used to monitor progress. Juvenile haemochromatosis is autosomal recessive and is generally associated with mutations in HJV (type 2A) or HAMP (type 2B). Mutations in TFR2 cause an intermediate severity phenotype (type 3), but this phenotype can cross over into the juvenile haemochromatosis spectrum so it might need to be additionally considered during diagnosis. Treatment needs to be administered without delay, in the form of aggressive iron chelation, and a multidisciplinary approach is essential. Because iron is removed, organ function is restored, which could obviate the need for cardiac or liver transplantation. Substantial restoration of health can ensue, but patients require life-long monitoring. Family screening is an important component of the management of juvenile haemochromatosis. Genetic advances which underpin the haemochromatosis types also clarify the role of iron metabolism in health and disease, particularly the role of hepcidin in regulating iron homoeostasis. Therefore, juvenile haemochromatosis is an important condition to understand; it can present insidiously in children and adolescents, and awareness of the diagnosis is needed to inform early recognition and treatment.