Interpretation of iron studies in adolescent haemochromatosis.

We report the case of a 14-year-old girl who originally presented at the age of eight with a history of bloody stools, abdominal pain and weight loss. Initial iron studies showed raised serum iron and transferrin saturation but low ferritin and were interpreted as consistent with iron deficiency under treatment. As she had not taken any supplemental iron she later underwent genetic testing for the Cys282Tyr and His63Asp mutations of the HFE gene. On the basis of these results, she was diagnosed as having hereditary haemochromatosis (HH). This case highlights that a low serum ferritin does not exclude the diagnosis of HH and that the availability of genetic testing can now enable probands and affected family members to be identified.