Genetic hemochromatosis in Italian patients with porphyria cutanea tarda: possible explanation for iron overload.

Background/aims: Mild to moderate iron overload is found in most patients with porphyria cutanea tarda. This study aimed to evaluate whether iron overload in patients with porphyria cutanea tarda is related to the presence of a coexistent genetic hemochromatosis gene.
Methods: A cohort study of 94 Italian patients with porphyria cutanea tarda (90 men and 4 women) and 20 relatives of five patients with iron overload were studied. Diagnosis of iron overload was assessed by transferrin saturation, serum ferritin and iron removed by phlebotomy to reach depletion. HLA typing by microlymphocytotoxicity test and duodenal ferritin analysis by immunohistochemistry were performed in a smaller number of patients. The chi square test was used to compare means and prevalences.
Results: Iron overload was present in 62% of the patients. HLA-A3 prevalence was significantly higher (p < 0.01) in subjects with iron overload than in those without. A lack of duodenal ferritin was observed in 14/18 patients with and in 6/12 without iron overload. Family studies showed the presence of iron overload but not of porphyria cutanea tarda in HLA identical or semi-identical relatives of the patients.
Conclusions: Italian patients with porphyria cutanea tarda and iron overload appear to have one or even two genes for genetic hemochromatosis.