Hypovitaminemia A in idiopathic hemochromatosis and hepatic cirrhosis. Role of retinol-binding protein and zinc.

Serum levels of vitamin A, its specific carrier protein retinol-binding protein (RBP), and zinc were determined in 34 cases of idiopathic hemochromatosis, 33 cases of alcoholic cirrhosis, 10 cases of non-alcoholic cirrhosis, and in 35 normal controls. In both alcoholic and non-alcoholic cirrhosis, vitamin A and RBP levels were very significantly reduced, whereas a significantly low zinc was observed only in the alcoholic cirrhosis group. In idiopathic hemochromatosis, vitamin A values were significantly lower compared to normals, whereas serum RBP levels were normal and serum zinc was very close to that of the controls. A significant correlation was found between vitamin A and RBP levels in the entire group of 112 patients. These results, (1) in alcoholic and non-alcoholic cirrhosis, confirm a dramatic vitamin A deficiency and the major role played by decreased RBP, but tend to deemphasize the possible role of zinc deficiency; (2) in idiopathic hemochromatosis, affirm a significant serum vitamin A deficiency supposedly by a different mechanism from that of alcoholic cirrhosis since in idiopathic hemochromatosis plasma RBP levels are normal. The role of this vitamin A disorder should be considered in the interpretation of clinical signs of idiopathic hemochromatosis such as ichthyosis and visual disorders.